Imaging device

ABSTRACT

The present invention relates to an image pickup apparatus which can produce a color and sensitivity mosaic image which can be converted into a color image signal having a wide dynamic range by performing a predetermined image process.  
     Light receiving elements of a CCD image sensor are arranged in a lattice arrangements where attention is paid to the color G irrespective of the sensitivities. Where attention is paid to the color R irrespective of the sensitivities, the light receiving elements are arranged on every other line. Also where attention is paid to the color B irrespective of the sensitivities, the light receiving elements are arranged on every other line similarly. Consequently, where attention is paid only to the colors of the pixels, the pattern P 2  has a Bayer arrangement. A mosaic arrangement of a color is realized by disposing an on-chip color filter on an upper face of the light receiving elements of the CCD image sensor. A mosaic arrangement of a sensitivity is realized by an optical method or an electronic method. The present invention can be applied, for example, to a CCD image sensor built in a digital camera.

TECHNICAL FIELD

[0001] This invention relates to an image pickup apparatus, and moreparticularly to an image pickup apparatus for use with a case wherein acolor and sensitivity mosaic image which can be converted into, forexample, a color image signal having a wide dynamic range is produced.

BACKGROUND ART

[0002] A solid-state image pickup device such as a CCD (Charge CoupledDevice) or a CMOS (Complementary Mental-Oxide Semiconductor) is utilizedwidely in image pickup apparatus such as a video camera and a digitalstill camera, part inspection apparatus in the field of the FA (FactoryAutomation) and optical measuring instruments such as an electronicendoscope in the field of the ME (Medical Electronics).

[0003] Conventionally, a method is known wherein light intensity signalsmeasured with different sensitivities among different pixels aresynthesized in order to increase the dynamic range of image pickupapparatus and optical measuring instruments in which a solid-state imagepickup device is used. In the following, first to fourth related-artmethods of the type mentioned are described.

[0004] As the first related-art method, a method can be listed whereinincoming light beams branched to a plurality of optical axes havingdifferent optical transmission factors are measured by solid-state imagepickup devices disposed on the individual optical axes. This method isdisclosed in the official gazette of Japanese Patent Laid-Open No. Hei8-223491 and so forth. However, the first method has a problem in thatit is disadvantageous in terms of the reduction of the cost or thereduction of the space because it requires a plurality of solid-stateimage pickup devices and a complicated optical system for branchinglight.

[0005] As the second related-art method, a method can be listed whereina single solid-state image pickup device is used such that the exposuretime thereof is divided into a plurality of time periods to pick up aplurality of images and then the images are synthesized. This method isdisclosed in the official gazette of Japanese Patent Laid-Open No. Hei8-331461 and so forth. However, the second method has a problem in thatan image of a dynamic scene in which the intensity of light varies everymoment cannot be picked up properly because the information measuredwith the different sensitivities are picked up at different points oftime and with different time widths.

[0006] As the third related-art method, a method can be listed wherein asingle solid-state image pickup device is used such that a plurality oflight receiving elements adjacent each other on an image pickup facethereof form a set which corresponds to one pixel of an output image andhave sensitivities different from each other to pick up an image. Thismethod is disclosed in the official gazette of U.S. Pat. No. 5,789,737.As a method for making the sensitivities of light receiving elementswhich form a solid-state image pickup device different from each other,a method is available wherein the light receiving elements are coveredwith filters having transmission factors different from each other.Further, a technique which adapts the third related-art method to acolor image is disclosed in the official gazette of Japanese PatentLaid-Open No. 2000-69491.

[0007] The third related-art method is advantageous in terms of thereduction of the cost and the reduction of the space in terms of whichthe first related-art method is disadvantageous. Further, the thirdrelated-art method can solve the problem of the second related-artmethod that an image of a dynamic scene cannot be picked up properly.However, with the third related-art method, since a plurality of lightreceiving elements adjacent each other form a set and correspond to onepixel of an output image, in order to secure a resolution of outputpixels, a number of image pickup devices including a number of lightreceiving elements equal to several times the number of pixels of theoutput image, resulting in a subject that a large unit cell size isrequired.

[0008] As the fourth related-art method, a method can be listed whereinan image pickup device having an ordinary dynamic range is used to pickup an image with a mechanism applied thereto which makes the exposuredifferent for each light receiving element corresponding to one pixel ofan output image and the resulting image signals are subject topredetermined image processing to produce an image signal of a widedynamic range. The mechanism for making the exposure different amongdifferent light receiving elements is implemented by producing a spatialsensitivity pattern by changing the light transmission factor or thenumerical aperture for each light receiving element. This method isdisclosed in a document ‘S. K. Nayar and T. Mitsunaga, “High DynamicRange Imaging: Spatially Varying Pixel Exposures”, Proc. of ComputerVision and Pattern Recognition 2000, Vol. 1, pp.472-479, June, 2000’.

[0009] In the fourth related-art method, each of the light receivingelements has only one kind of sensitivity. Consequently, each of pixelsof an image picked up can acquire information of a dynamic range whichthe image pickup device originally has. However, by applyingpredetermined image processing to resulting image signals so that thesensitivities of all of the pixels may become equal to one another, animage having a wide dynamic range can be produced. Further, since all ofthe light receiving elements are exposed to light at the same time, animage of a subject having some movement can be picked up properly.Furthermore, since one light receiving element corresponds to one pixelof output image, the problem that a great unit size is required does notoccur with the fourth related-art method.

[0010] As described above, the fourth related-art method can solve theproblems of the first to third related-art methods. However, the fourthrelated-art method has a premise that a monochromatic image is produced,and has a subject that a technique for producing a color image has notbeen established. More particularly, the fourth related-art method has asubject that a technique of producing image signals of all colorcomponents for all pixels from an image having different colors and/ordifferent sensitivities among different pixels and making thesensitivity uniform has not conventionally been established.

DISCLOSURE OF INVENTION

[0011] The present invention has been made in such a situation asdescribed above, and it is an object of the present invention to make itpossible to produce a color and sensitivity mosaic image which can beconverted into a color image signal having a wide dynamic range byperforming a predetermined image process.

[0012] A first image pickup apparatus of the present invention ischaracterized in that photo-electric conversion means produces a colorand sensitivity mosaic image wherein a plurality of pixels having thesame color components and the same sensitivity characteristics arearranged in lattice arrangements and a plurality of pixels having thesame color components irrespective of the sensitivity characteristicsare arranged in lattice arrangements.

[0013] The plurality of color components may be the three primary colorcomponents.

[0014] The photo-electric conversion means may produce the color andsensitivity mosaic image which has a Bayer arrangement where attentionis paid only to the color components.

[0015] A second image pickup apparatus of the present invention ischaracterized in that photo-electric conversion means produces a colorand sensitivity mosaic image wherein a plurality of pixels having thesame color components and the same sensitivity characteristics arearranged in lattice arrangements and a plurality of pixels having thesame sensitivity characteristics irrespective of the color componentsare arranged in lattice arrangements, and that all of the colorcomponents included in the color and sensitivity mosaic image exist intotaling five pixels including an arbitrary pixel of the color andsensitivity mosaic image and four pixels neighboring upwardly,downwardly, leftwardly and rightwardly of the arbitrary pixel.

[0016] The plurality of color components may be the three primary colorcomponents.

[0017] The photo-electric conversion means may produce the color andsensitivity mosaic image wherein the pixels form a Bayer arrangement foreach of the sensitivity characteristics.

[0018] A first image pickup device of the present invention ischaracterized in that it produces a color and sensitivity mosaic imagewherein a plurality of pixels having the same color components and thesame sensitivity characteristics are arranged in lattice arrangementsand a plurality of pixels having the same color components irrespectiveof the sensitivity characteristics are arranged in lattice arrangements.

[0019] The plurality of color components may be the three primary colorcomponents.

[0020] A second image pickup device of the present invention ischaracterized in that it produces a color and sensitivity mosaic imagewherein a plurality of pixels having the same color components and thesame sensitivity characteristics are arranged in lattice arrangementsand a plurality of pixels having the same sensitivity characteristicsirrespective of the color components are arranged in latticearrangements, and that all of the color components included in the colorand sensitivity mosaic image exist in totaling five pixels including anarbitrary pixel of the color and sensitivity mosaic image and fourpixels neighboring upwardly, downwardly, leftwardly and rightwardly ofthe arbitrary pixel.

[0021] The plurality of color components may be the three primary colorcomponents.

[0022] In the first image pickup apparatus of the present invention, thephoto-electric conversion means produces a color and sensitivity mosaicimage wherein a plurality of pixels having the same color components andthe same sensitivity characteristics are arranged in latticearrangements and a plurality of pixels having the same color componentsirrespective of the sensitivity characteristics are arranged in latticearrangements.

[0023] In the second image pickup apparatus of the present invention,the photo-electric conversion means produces a color and sensitivitymosaic image wherein a plurality of pixels having the same colorcomponents and the same sensitivity characteristics are arranged inlattice arrangements and a plurality of pixels having the samesensitivity characteristics irrespective of the color components arearranged in lattice arrangements such that all of the color componentsincluded in the color and sensitivity mosaic image exist in totalingfive pixels including an arbitrary pixel of the color and sensitivitymosaic image and four pixels neighboring upwardly, downwardly,leftwardly and rightwardly of the arbitrary pixel.

[0024] In the first image pickup device of the present invention, acolor and sensitivity mosaic image is produced wherein a plurality ofpixels having the same color components and the same sensitivitycharacteristics are arranged in lattice arrangements and a plurality ofpixels having the same color components irrespective of the sensitivitycharacteristics are arranged in lattice arrangements.

[0025] In the second image pickup device of the present invention, acolor and sensitivity mosaic image is produced wherein a plurality ofpixels having the same color components and the same sensitivitycharacteristics are arranged in lattice arrangements and a plurality ofpixels having the same sensitivity characteristics irrespective of thecolor components are arranged in lattice arrangements such that all ofthe color components included in the color and sensitivity mosaic imageexist in totaling five pixels including an arbitrary pixel of the colorand sensitivity mosaic image and four pixels neighboring upwardly,downwardly, leftwardly and rightwardly of the arbitrary pixel.

BRIEF DESCRIPTION OF DRAWINGS

[0026]FIG. 1 is a block diagram showing an example of a configuration ofa digital still camera to which the present invention is applied;

[0027]FIG. 2 is a view illustrating general operation of the digitalstill camera;

[0028]FIG. 3 is a view showing an example of a subject;

[0029]FIG. 4 is a view showing an example of a color and sensitivitymosaic image corresponding to the example of FIG. 3;

[0030]FIG. 5 is a view showing a color and sensitivity mosaic patternP1;

[0031]FIG. 6 is a view showing a color and sensitivity mosaic patternP2;

[0032]FIG. 7 is a view showing a color and sensitivity mosaic patternP3;

[0033]FIG. 8 is a view showing a color and sensitivity mosaic patternP4;

[0034]FIG. 9 is a view showing a color and sensitivity mosaic patternP5;

[0035]FIG. 10 is a view showing a color and sensitivity mosaic patternP6;

[0036]FIG. 11 is a view showing a color and sensitivity mosaic patternP7;

[0037]FIG. 12 is a view showing a color and sensitivity mosaic patternP8;

[0038]FIG. 13 is a view showing a color and sensitivity mosaic patternP9;

[0039]FIG. 14 is a view showing a color and sensitivity mosaic patternP10;

[0040]FIG. 15 is a view showing a color and sensitivity mosaic patternP11;

[0041]FIG. 16 is a view showing a color and sensitivity mosaic patternP12;

[0042]FIG. 17 is a view showing a color and sensitivity mosaic patternP13;

[0043]FIG. 18 is a view showing a color and sensitivity mosaic patternP14;

[0044]FIG. 19 is a view showing a cross section of a light receivingelement of a CCD image sensor 4;

[0045]FIG. 20 is a view illustrating a method for optically implementinga mosaic arrangement of sensitivity;

[0046]FIG. 21 is a view illustrating another method for opticallyimplementing a mosaic arrangement of sensitivity;

[0047]FIG. 22 is a view illustrating a further method for opticallyimplementing a mosaic pattern of sensitivity;

[0048]FIG. 23 is a view illustrating a first method for electronicallyimplementing a mosaic pattern of sensitivity;

[0049]FIG. 24 is a view illustrating a second method for electronicallyimplementing a mosaic pattern of sensitivity;

[0050]FIG. 25 is a schematic view showing an OR-type electrodestructure;

[0051]FIG. 26 is a sectional view showing a cross section of the OR-typeelectrode structure;

[0052]FIG. 27 is a schematic view showing an AND-type electrodestructure;

[0053]FIG. 28 is a view showing a combination of the OR-type electrodestructure and the AND-type electrode structure for implementing thecolor and sensitivity mosaic pattern PI;

[0054]FIG. 29 is a view showing a combination of the OR-type electrodestructure and the AND-type electrode structure for implementing thecolor and sensitivity mosaic pattern P2;

[0055]FIG. 30 is a view showing a combination of the OR-type electrodestructure and the AND-type electrode structure for implementing thecolor and sensitivity mosaic pattern P3;

[0056]FIG. 31 is a view showing a combination of the OR-type electrodestructure and the AND-type electrode structure for implementing thecolor and sensitivity mosaic pattern P4;

[0057]FIG. 32 is a view showing a combination of the OR-type electrodestructure and the AND-type electrode structure for implementing thecolor and sensitivity mosaic pattern P5;

[0058]FIG. 33 is a view illustrating a definition of positioncoordinates of a pixel;

[0059]FIG. 34 is a view illustrating an outline of a first demosaicprocess;

[0060]FIG. 35 is a graph illustrating an outline of a first sensitivityuniformization process in the first demosaic process;

[0061]FIG. 36 is a graph illustrating an outline of the firstsensitivity uniformization process in the first demosaic process;

[0062]FIG. 37 is a graph illustrating an outline of the firstsensitivity uniformization process in the first demosaic process;

[0063]FIG. 38 is a graph illustrating an outline of a second sensitivityuniformization process in the first demosaic process;

[0064]FIG. 39 is a graph illustrating an outline of the secondsensitivity uniformization process in the first demosaic process;

[0065]FIG. 40 is a view illustrating an outline of a second demosaicprocess;

[0066]FIG. 41 is a graph illustrating an outline of a first sensitivityuniformization process in the second demosaic process;

[0067]FIG. 42 is a graph illustrating an outline of the firstsensitivity uniformization process in the second demosaic process;

[0068]FIG. 43 is a graph illustrating an outline of a second sensitivityuniformization process in the second demosaic process;

[0069]FIG. 44 is a graph illustrating an outline of the secondsensitivity uniformization process in the second demosaic process;

[0070]FIG. 45 is a block diagram showing a first example of aconfiguration of an image processing section 7;

[0071]FIG. 46 is a block diagram showing a first example of aconfiguration of a sensitivity uniformization section 51;

[0072]FIG. 47 is a block diagram showing an example of a configurationof a color interpolation section 52;

[0073]FIG. 48 is a block diagram showing an example of a configurationof a color difference image production section 72;

[0074]FIG. 49 is a block diagram showing an example of a configurationof a luminance image production section 74;

[0075]FIG. 50 is a flow chart illustrating the first demosaic process bythe first example of the configuration of the image processing section7;

[0076]FIG. 51 is a flow chart illustrating the first sensitivityuniformization process by the first example of the configuration of thesensitivity uniformization section 51;

[0077]FIG. 52 is a flow chart illustrating a sensitivity compensationprocess at step S11;

[0078]FIG. 53 is a flow chart illustrating a validity discriminationprocess at step S12;

[0079]FIG. 54 is a flow chart illustrating a missing interpolationprocess at step S13;

[0080]FIG. 55 is a flow chart illustrating a color interpolation processat step S2;

[0081]FIG. 56 is a flow chart illustrating a first color differenceimage production process at step S52;

[0082]FIG. 57 is flow chart illustrating a luminance image productionprocess at step S53;

[0083]FIG. 58 is a flow chart illustrating a color space conversionprocess at step S54;

[0084]FIG. 59 is a block diagram showing a second example of aconfiguration of the sensitivity uniformization section 51;

[0085]FIG. 60 is a flow chart illustrating a second sensitivityuniformization process by the second example of the configuration of thesensitivity uniformization section 51;

[0086]FIG. 61 is a flow chart illustrating an interpolation process atstep S103;

[0087]FIG. 62 is a flow chart illustrating a second color differenceimage production process;

[0088]FIG. 63 is a flow chart illustrating an image gradient vectorarithmetic operation process at step S123;

[0089]FIG. 64 is a block diagram showing a second example of aconfiguration of the image processing section 7;

[0090]FIG. 65 is a block diagram showing a first example of aconfiguration of a sensitivity uniformization section 111;

[0091]FIG. 66 is a flow chart illustrating a missing interpolationprocess by a missing interpolation section 124;

[0092]FIG. 67 is a block diagram showing a second example of aconfiguration of the sensitivity uniformization section 111;

[0093]FIG. 68 is a flow chart illustrating the second sensitivityuniformization process in the second demosaic process by the secondexample of the configuration of the sensitivity uniformization section111;

[0094]FIG. 69 is a flow chart illustrating an interpolation colordetermination process at step S163;

[0095]FIG. 70 is a view illustrating an outline of a third demosaicprocess;

[0096]FIG. 71 is a view illustrating an outline of aby-sensitivity-basis color interpolation process in the third demosaicprocess;

[0097]FIG. 72 is a view illustrating an outline of theby-sensitivity-basis color interpolation process in the third demosaicprocess;

[0098]FIG. 73 is a block diagram showing a third example of aconfiguration of the image processing section 7;

[0099]FIG. 74 is a block diagram showing an example of a configurationof a by-sensitivity-basis color interpolation section 151;

[0100]FIG. 75 is a block diagram showing an example of a configurationof a sensitivity uniformization section 152;

[0101]FIG. 76 is a flow chart illustrating the third demosaic process bythe third example of the configuration of the image processing section7;

[0102]FIG. 77 is a flow chart illustrating the by-sensitivity-basiscolor interpolation process at step S181;

[0103]FIG. 78 is a view illustrating an extraction process at step S193;

[0104]FIG. 79 is a view illustrating the extraction process at stepS193;

[0105]FIG. 80 is a flow chart illustrating a sensitivity uniformizationprocess at step S182;

[0106]FIG. 81 is a view showing an example of a filter coefficient usedin a local sum calculation process at step S203;

[0107]FIG. 82 is a block diagram showing a fourteen example of aconfiguration of the image processing section 7;

[0108]FIG. 83 is a block diagram showing a first example of aconfiguration of a luminance image production section 181;

[0109]FIG. 84 is a block diagram showing an example of a configurationof a monochromatic image production section 182;

[0110]FIG. 85 is a flow chart illustrating a fourth demosaic process bythe fourth example of the configuration of the image processing section7;

[0111]FIG. 86 is a flow chart illustrating a luminance image productionprocess by the luminance image production section 181;

[0112]FIG. 87 is a flow chart illustrating an R component estimationprocess by an estimation section 191;

[0113]FIG. 88 is a view showing an example of interpolation filtercoefficients for R/B components;

[0114]FIG. 89 is a view showing interpolation filter coefficients for aG component;

[0115]FIG. 90 is a view illustrating a synthetic sensitivitycompensation LUT;

[0116]FIG. 91 is a view illustrating another synthetic sensitivitycompensation LUT;

[0117]FIG. 92 is a view illustrating a further synthetic sensitivitycompensation LUT;

[0118]FIG. 93 is a flow chart illustrating a noise removal process by anoise removal section 198;

[0119]FIG. 94 is a flow chart illustrating a direction selectivesmoothing process by the noise removal section 198;

[0120]FIG. 95 is a flow chart illustrating a monochromatic imageproduction process by the monochromatic image production section 182;

[0121]FIG. 96 is a flow chart illustrating a ratio value calculationprocess by a ratio value calculation section 202;

[0122]FIG. 97 is a view illustrating an example of smoothing filtercoefficients;

[0123]FIG. 98 is a block diagram showing a second example of aconfiguration of the luminance image production section 181;

[0124]FIG. 99 is a flow chart illustrating an estimation process of RGBcomponents by an estimation section 211;

[0125]FIG. 100 is a view showing an arrangement of pixels used in anestimation pixel value C0 interpolation process;

[0126]FIG. 101 is a flow chart illustrating the estimation pixel valueC0 interpolation process;

[0127]FIG. 102 is a view showing an arrangement of pixels used in anestimation pixel value C1 interpolation process;

[0128]FIG. 103 is a flow chart illustrating the estimation pixel valueC1 interpolation process;

[0129]FIG. 104A is a view showing an arrangement of pixels used in anestimation pixel value C2 interpolation process;

[0130]FIG. 104B is a view showing another arrangement of pixels used inthe estimation pixel value C2 interpolation process;

[0131]FIG. 105 is a flow chart illustrating the estimation pixel valueC2 interpolation process;

[0132]FIG. 106 is a view showing an arrangement of pixels used in anestimation pixel value C3 interpolation process;

[0133]FIG. 107 is a flow chart illustrating the estimation pixel valueC3 interpolation process;

[0134]FIG. 108 is a flow chart illustrating an R candidate imageproduction process by an interpolation section 201-R;

[0135]FIG. 109 is a flow chart illustrating a B candidate imageproduction process by an interpolation section 201-B;

[0136]FIG. 110 is a flow chart illustrating a G candidate imageproduction process by an interpolation section 201-G; and

[0137]FIG. 111 is a block diagram showing a fifth example of aconfiguration of the image processing section 7.

BEST MODE FOR CARRYING OUT THE INVENTION

[0138]FIG. 1 shows an example of a configuration of a digital stillcamera which is an embodiment of the present invention. The digitalstill camera is roughly composed of an optical system, a signalprocessing system, a recording system, a display system and a controlsystem.

[0139] The optical system includes a lens 1 for condensing an opticalimage of a subject, an iris 2 for adjusting the amount of light of theoptical image, and a CCD image sensor 4 for photo-electricallyconverting the condensed optical image into an electric signal of a widedynamic range.

[0140] The signal processing system includes a correlation doublesampling circuit (CDS) 5 for sampling an electric signal from the CCDimage sensor 4 to reduce noise of the electric signal, an A/D converter6 for converting an analog signal outputted from the correlation doublesampling circuit 5 into a digital signal, and an image processingsection 7 for performing a predetermined image process for the digitalsignal inputted thereto from the A/D converter 6. It is to be noted thatdetails of the process executed by the image processing section 7 arehereinafter described.

[0141] The recording system includes a CODEC (Compression/Decompression)8 for coding and recording an image signal processed by the imageprocessing section 7 into a memory 9 and reading out, decoding andsupplying the image signal to the image processing section 7, and thememory 9 for storing an image signal.

[0142] The display system includes a D/A converter 10 for converting animage signal processed by the image processing section 7 into an analogsignal, a video encoder 11 for encoding the analog image signal into avideo signal of the format compatible with a display unit 12 in thefollowing stage, and a display unit 12 formed from an LCD (LiquidCrystal Display) unit or the like for displaying an image correspondingto the video signal inputted thereto so that it functions as aviewfinder.

[0143] The control system includes a timing generator (TG) 3 forcontrolling operation timings of the components from the CCD imagesensor 4 to the image processing section 7, an operation inputtingsection 13 for allowing the user to input a shutter timing and othercommands, and a control section 14 including a CPU (Central ProcessingUnit) and so forth for controlling a drive 15 to read out a controllingprogram stored on a magnetic disc 16, an optical disc 17, amagneto-optical disc 18 or a semiconductor memory 19 and controlling theentire digital still camera based on the controlling program read out, acommand from the user inputted from the operation inputting section 13and so forth.

[0144] In the digital still camera, an optical image (incoming light) ofa subject is introduced into the CCD image sensor 4 through the lens 1and the iris 2, and it is photo-electrically converted by the CCD imagesensor 4. The resulting electric signal is subject to removal of noiseby the correlation double sampling circuit 5 and is then converted intoa digital signal by the A/D converter 6, whereafter it is temporarilystored into an image memory built in the image processing section 7.

[0145] It is to be noted that, in an ordinary state, an image signal isincessantly overwritten at a fixed frame rate into the image memorybuilt in the image processing section 7 under the control of the timinggenerator 3 for the signal processing system. The image signal of theimage memory built in the image processing section 7 is converted intoan analog signal by the D/A converter 10 and further converted into avideo signal by the video encoder 11, and a corresponding image isdisplayed on the display unit 12.

[0146] The display unit 12 further has a function as a viewfinder of thedigital still camera. When the user depresses a shutter button includedin the operation inputting section 13, the control section 14 controlsthe timing generator 3 so that the signal processing system fetches animage signal immediately after the shutter button is depressed andthereafter inhibits an image signal from being overwritten into theimage memory of the image processing section 7. Thereafter, the imagedata written in the image memory of the image processing section 7 arecoded by the CODEC 8 and recorded into the memory 9. Fetching of imagedata of one frame is completed by such operation of the digital stillcamera as described above.

[0147] Subsequently, an outline of operation of the digital still camerais described with reference to FIG. 2. The digital still camera picks upan image of a subject with a color and a sensitivity, which aredifferent for each pixel, through an image pickup process of the opticalsystem including the CCD image sensor 4 as a principal component toobtain an image wherein colors and sensitivities are distributed like amosaic (such an image as just described is hereinafter referred to ascolor and sensitivity mosaic image, whose details are hereinafterdescribed). Thereafter, the image obtained by the image pickup processis converted into an image wherein each pixel has all color componentsand the pixels have a uniform sensitivity by the signal processingsystem which includes the image processing section 7 as a principalcomponent. In the following description, the process of the signalprocessing system including the image processing section 7 as aprincipal component for converting a color and sensitivity mosaic imageinto an image wherein each pixel has all color components and the pixelshave a uniform sensitivity is referred to as demosaic process.

[0148] For example, if an image of such a subject as shown in FIG. 3 ispicked up, then such a color and sensitivity mosaic image as shown inFIG. 4 is obtained through the image pickup process and is convertedinto an image wherein each pixel has all color components and the pixelshave a uniform sensitivity through the image process. In particular, theoriginal colors of the subject shown in FIG. 3 are restored from thecolor and sensitivity mosaic image shown in FIG. 4.

[0149] Arrangement patterns (hereinafter referred to as color andsensitivity mosaic patterns) P1 to P14 of color components andsensitivities of pixels which compose a color and sensitivity mosaicimage are shown in FIGS. 5 to 18, respectively. It is to be noted that,as a combination of colors which form a color and sensitivity mosaicpattern, a combination of three colors of R (red), G (green) and B(blue) and another combination of four colors of Y (yellow), M(magenta), C (cyan) and G (green) are available. As stages of thesensitivity, two stages of S0 and S1, three stages which additionallyinclude a sensitivity S2 and four stages which additionally include afurther sensitivity S3 are available. It is to be noted that, in FIGS. 5to 18, each square corresponds to one pixel, and an alphabetical letterrepresents the color of the pixel and a numeral as a subscript to thealphabetical letter represents the sensitivity of the pixel. Forexample, a pixel denoted by G₀ represents that the color thereof is G(green) and the sensitivity thereof is S0. Further, it is assumed that,as regards the sensitivity, the higher the value, the higher thesensitivity.

[0150] The color and sensitivity mosaic patterns P1 to P14 can beclassified based on the first to fourth characteristics described below.

[0151] The first characteristic is that, where attention is paid tothose pixels which have the same color and the same sensitivity, theyare arranged like a lattice, and where attention is paid to those pixelswhich have the same color irrespective of the sensitivity, they arearranged like a lattice. The first characteristic is described withreference to the color and sensitivity mosaic pattern P1 shown in FIG.5.

[0152] In the color and sensitivity mosaic pattern P1 of FIG. 5, whereattention is paid to those pixels which have the color R irrespective ofthe sensitivity, as can be seen apparently if the figure is viewed in astate rotated by 45 degrees in the clockwise direction, they arearranged like a lattice wherein they are spaced from each other by 2½ inthe horizontal direction and by 2{fraction (3/2)} in the verticaldirection. Further, where attention is paid to those pixels which havethe color B irrespective of the sensitivity, also they are arranged likea lattice wherein they are spaced from each other by 2½ in thehorizontal direction and by 2{fraction (3/2)} in the vertical direction.Further, where attention is paid to those pixels which have the color Girrespective of the sensitivity, also they are arranged like a latticewherein they are spaced from each other by 2½ both in the horizontaldirection and in the vertical direction.

[0153] In addition to the color and sensitivity mosaic pattern P1 shownin FIG. 5, the color and sensitivity mosaic patterns P2, P4, P6, P8, P9,P10, P11 and P13 have the first characteristic.

[0154] The second characteristic is that, where attention is paid tothose pixels which have the same color and the same sensitivity, theyare arranged like a lattice, and where attention is paid to those pixelswhich have the same sensitivity irrespective of the color, they arearranged like a lattice, and besides, where attention is paid to anarbitrary pixel, all of colors included in the color and sensitivitymosaic pattern are included in colors which totaling five pixelsincluding the pixel and four pixels positioned upwardly, downwardly,leftwardly and rightwardly of the pixel have.

[0155] In addition to the color and sensitivity mosaic pattern P3 shownin FIG. 7, the color and sensitivity mosaic patterns P5, P7, P8, P9, P12and P14 have the second characteristic.

[0156] The third characteristic is that the color and sensitivity mosaicpattern has the first characteristic and uses three different colors andthe pixels of the colors are arranged in a Bayer arrangement. The thirdcharacteristic is described with reference to the color and sensitivitymosaic pattern P2 shown in FIG. 6.

[0157] Where attention is paid to those pixels of the color andsensitivity mosaic pattern P2 of FIG. 6 which have the color Girrespective of the sensitivity, they are arranged alternately in acheckered pattern. Where attention is paid to those pixels which havethe color R irrespective of the sensitivity, they are arranged on everyother line. Further, also where attention is paid to those pixels whosecolor is B irrespective of the sensitivity, they are arranged on everyother line similarly. Accordingly, the pattern P2 has a Bayerarrangement where attention is paid only to the colors of the pixels.

[0158] It is to be noted that, in addition to the color and sensitivitymosaic pattern P2 of FIG. 6, the color and sensitivity mosaic patternsP10 and P11 have the third characteristic.

[0159] The fourth characteristic is that the color and sensitivitymosaic pattern has the second characteristic and further, whereattention is paid to those pixels which have the same sensitivity, thearrangement of them is a Bayer arrangement. The fourth characteristic isdescribed with reference to the color and sensitivity mosaic pattern P3shown in FIG. 7.

[0160] Where attention is paid only to those pixels in the color andsensitivity mosaic pattern P3 shown in FIG. 7 which have the sensitivityS0, as can be seen apparently if the figure is viewed obliquely in astate inclined by 45 degrees, they are arranged in a spaced relationshipby a distance of 2½ and in a Bayer arrangement. Also where attention ispaid to those pixels which have the sensitivity S1, they are arranged ina Bayer arrangement similarly.

[0161] It is to be noted that, in addition to the color and sensitivitymosaic pattern P3 of FIG. 7, the color and sensitivity mosaic patternsP5 and P12 have the fourth characteristic.

[0162] Incidentally, an arrangement of any of the color and sensitivitymosaic patterns P1 to P14 shown in FIGS. 5 to 18 is hereinafter referredto as “color mosaic arrangement” where attention is paid only to thecolors of the pixels irrespective of the sensitivity, but is hereinafterreferred to as “sensitivity mosaic arrangement” where attention is paidonly to the sensitivities irrespective of the color.

[0163] Subsequently, a method of implementing the color and sensitivitymosaic patterns described above on the CCD image sensor 4 is described.

[0164] Of the color and sensitivity mosaic patterns, the color mosaicarrangements are implemented by disposing an on-chip color filter, whichpasses only light of a different color for each pixel, on an upper faceof a light receiving element of the CCD image sensor 4.

[0165] Of the color and sensitivity mosaic patterns, the sensitivitymosaic arrangements are implemented by an optical method or anelectronic method.

[0166] A method of optically implementing a sensitivity mosaicarrangement is described. FIG. 19 shows a cross section of a lightreceiving element of the CCD image sensor 4. An on-chip lens 21 isformed on an upper surface of the light receiving element. The on-chiplens 21 is disposed so that it condenses incoming light from an upperportion of the figure on a photo-diode (PD) 23. An on-chip color filter22 limits a wavelength band of the incoming light (passes only aparticular wavelength band therethrough). The photo-diode 23 is formedin a wafer at a lower portion of the light receiving element. Thephoto-diode 23 produces electric charge in response to the amount oflight inputted thereto. A vertical register 26 is formed on the oppositesides of the photo-diode 21. A pair of vertical register drivingelectrodes 25 for driving the vertical register 21 are wired above thevertical register 26.

[0167] Since the vertical register 26 is a region for transferringelectric charge produced by the photo-diode 23, the vertical register 26and the vertical register driving electrodes 25 are shielded from lightby a shield 24 so that no electric charge may be produced in thevertical register 26. The shield 24 is open only above the photo-diode23 such that the incoming light may pass the opening portion until itreaches the photo-diode 23.

[0168] The sensitivity of each light receiving element can be varied(the amount of incoming light to the photo-diode 23 can be varied)making use of the CCD image sensor 4 configured in such a manner asdescribed above.

[0169] For example, the amount of condensed light can be varieddepending upon whether or not the on-chip lens 21 is disposed as seen inFIG. 20. Meanwhile, the light transmission factor can be varied, forexample, by disposing a neutral density filter 31 above (or below) theon-chip color filter 22 as seen in FIG. 21. Further, the incoming lightamount to the photo-diode 23 can be varied, for example, by varying thearea of the opening portion of the shield 24 as seen in FIG. 22.

[0170] Now, two different methods for electronically implementing amosaic arrangement of sensitivity are described.

[0171] For example, a first method of setting two adjacent lightreceiving elements (first and second light receiving elements) todifferent sensitivities by changing the timing of control is describedwith reference to FIG. 23.

[0172] The first stage of FIG. 23 shows an exposure period of the CCDimage sensor 4. The second stage of FIG. 23 shows a timing of a pulsevoltage for instruction of sweeping out of electric charge. The thirdstage of FIG. 23 shows a timing at which a control voltage forinstruction of charge transfer is applied. The fourth stage of FIG. 23shows a timing of a pulse voltage for instructing a first lightreceiving element to read out electric charge. The fifth stage of FIG.23 shows a variation of the electric charge amount accumulated in thefirst light receiving element in response to application of the chargesweeping out pulse voltage and the charge reading out pulse voltage. Thesixth stage of FIG. 23 shows a timing of a pulse voltage for instructinga second light receiving element to read out electric charge. Theseventh stage of FIG. 23 shows a variation of the electric charge amountaccumulated in the second light receiving element in response toapplication of the charge sweeping out pulse voltage and the chargereading out pulse voltage.

[0173] In the first method of electronically implementing a sensitivitymosaic arrangement, the charge sweeping out pulse voltage is suppliedcommonly to the first and second light receiving elements so that,except within an exposure period, electric charge is swept out (reset)from the photo-diode 23, but within an exposure period, electric chargeis reset only once at a predetermined timing.

[0174] The charge transfer voltage is supplied, except within anexposure period, as a waveform voltage for transferring electric chargeto the vertical register 26 commonly to the first and second lightreceiving elements, but is not supplied, within an exposure period, sothat transfer of electric charge from the vertical register 26 may bestopped.

[0175] The charge reading out pulse voltage is supplied at differenttimings to the light receiving elements. To the first light receivingelement, the charge reading out pulse voltage for the first time issupplied immediately before the supplying timing of the charge sweepingout voltage within an exposure period (second stage of FIG. 23), but thecharge reading out pulse voltage for the second time is suppliedimmediately before the end of the exposure period.

[0176] As a result, from the first light receiving element, theaccumulated charge amount of the first light receiving element is readout into the vertical register 26 at the supplying timings of the chargereading out pulse voltage for the first and second times. It is to benoted that, since transfer of electric charge of the vertical register26 stops within an exposure period, the electric charge amounts read outtwice are added in the vertical register 26 and transferred as data ofthe same frame from the vertical register 26 after the end of theexposure period.

[0177] Meanwhile, to the second light receiving element, the chargereading out pulse voltage is supplied only once immediately before thesupplying timing of the charge sweeping out pulse voltage within anexposure period. As a result, from the second light receiving element,the accumulated electric charge amount of the second light receivingelement at the only one supplying timing of the charge reading out pulsevoltage is read out into the vertical register 26. It is to be notedthat, since transfer of electric charge of the vertical register 23stops within an exposure period, the accumulated electric charge readout from the second light receiving element is transferred as data ofthe same frame as that of the accumulated electric charge read out fromthe first light receiving element from the vertical register 26 afterthe end of the exposure period.

[0178] By making the control timings for the first light receivingelement and the second light receiving element different from each otherin this manner, it is possible to set so that the accumulated electriccharge amount read out from the first light receiving element and theaccumulated electric charge amount read out from the second lightreceiving element within the same exposure period, or in other words,the sensitivities, may be different from each other.

[0179] Incidentally, the first method of electronically implementing asensitivity mosaic arrangement has a problem in that, depending upon alight receiving element, information of a subject cannot be measuredover an overall region within an exposure period.

[0180] Now, a second method of electronically implementing a sensitivitymosaic arrangement is described with reference to FIG. 24. The first tosixth stages of FIG. 24 show, similarly to the first to sixth stages ofFIG. 23, an exposure period of the CCD image sensor 4, a timing of apulse voltage for instruction of sweeping out of electric charge, atiming at which a control voltage for instruction of charge transfer isapplied, a timing of a pulse voltage for instructing the first lightreceiving element to read out electric charge, a variation of theelectric charge amount accumulated in the first light receiving elementin response to application of the charge sweeping out pulse voltage andthe charge reading out pulse voltage, a timing of a pulse voltage forinstructing the second light receiving element to read out electriccharge, and a variation of the electric charge amount accumulated in thesecond light receiving element in response to application of the chargesweeping out pulse voltage and the charge reading out pulse voltage.

[0181] In the second method of electronically implementing a sensitivitymosaic arrangement, the charge sweeping out pulse voltage and the chargereading out pulse voltage are supplied repetitively by a plural numberof times within an exposure period.

[0182] In particular, as regards the charge sweeping out pulse voltage,a set of the charge sweeping out pulse voltage for the first time andthe charge sweeping out pulse voltage for the second time are suppliedby a plural number of times commonly to the first and second lightreceiving elements within an exposure period. As regards the chargereading out pulse voltage, to the first light receiving element, thecharge reading out pulse voltage for the first time is supplied, foreach set of the charge sweeping out pulse voltages for the first andsecond times, immediately before the charge sweeping out pulse voltagefor the first time, and the charge reading out pulse voltage for thesecond time is supplied immediately before the charge sweeping out pulsevoltage for the second time. Meanwhile, to the second light receivingelement, for each set of the charge sweeping out pulse voltages, thecharge reading out pulse voltage is supplied only once immediatelybefore the charge sweeping out pulse voltage for the first time.

[0183] As a result, for each set of the charge sweeping out pulsevoltages for the first and second times, the accumulated charge amountof the first light receiving element at the supplying timing of thecharge reading out pulse voltage for the first time and the accumulatedcharge amount of the first light receiving element at the supplyingtiming of the charge reading out pulse voltage for the second time areread out from the first light receiving element. It is to be noted that,within an exposure period, since transfer of charge of the verticalregister 26 stops, the charge amounts read out twice for each set areadded by the vertical register 26. From the second light receivingelement, the accumulated charge amount of the second light receivingelement at the supplying timing of the charge reading out pulse voltagewhich is supplied only once for each set of the charge sweeping outpulse voltage for the first and second times is read out. The chargeamount read out once for each set is added by the vertical register 26.

[0184] In such a second method for electronically implementing asensitivity mosaic arrangement as described above, since reading out ofcharge is repeated by a plural number of times within an exposureperiod, information of the subject over an overall region of theexposure period can be measured.

[0185] It is to be noted that, in connection with the first and secondmethods for electronically implementing a sensitivity mosaic arrangementdescribed above, reading out control of the CCD image sensor 4 isusually applied to the vertical register driving electrodes 25 wired foreach horizontal line. For example, in order to implement a sensitivitymosaic arrangement wherein the sensitivity changes for each horizontalline as in the color and sensitivity mosaic pattern P1 shown in FIG. 5,the electrode structure may be utilized, and therefore, someimprovements which allow application of different reading out pulsevoltages to different lines should be made. Further, in a CCD imagesensor of the progressive scanning type having a 3-phase driven verticalregister, an arbitrary mosaic arrangement with two different sensitivitystages can be implemented electronically by devising the electrodestructure.

[0186]FIG. 25 shows a first electrode structure of a poly-siliconelectrode for vertical transfer by an electrode wiring line used toimplement a sensitivity mosaic arrangement having two stages ofsensitivity. FIG. 26 shows a cross sectional view of the CCD imagesensor taken along line a-a′ of FIG. 25. Each of a first phase verticalregister driving electrode 42 and a second phase vertical registerdriving electrode 43 is connected to electrodes of adjacent pixels onthe same horizontal line, and therefore, the electrodes on the samehorizontal line are driven in synchronism. Meanwhile, a third phasevertical register driving electrode 44 is connected to electrodes ofadjacent pixels on the same vertical line, and therefore, the electrodeson the same vertical line are driven in synchronism. Further, the secondphase vertical register driving electrode 43 and the third phasevertical register driving electrode 44 overly a reading out gate 41adjacent the corresponding photo-diode 23.

[0187] Accordingly, when a reading out pulse is applied to the secondphase vertical register driving electrode 43 or the third phase verticalregister driving electrode 44, the barrier of the reading out gate 41can be temporarily removed to allow charge accumulated in thecorresponding photo-diode 23 to be transferred to the vertical register26. In the following description, the electrode structure shown in FIGS.25 and 26 is referred to as OR type electrode structure.

[0188]FIG. 27 shows a second electrode structure of a poly-siliconelectrode for vertical transfer by electrode wiring lines used toimplement a sensitivity mosaic arrangement having two stages ofsensitivity. Also the cross section of the CCD image sensor taken alongline a-a′ of FIG. 27 is similar to that of the cross sectional viewshown in FIG. 26. In particular, also in the second electrode structure,similarly to the first electrode structure, each of the first phasevertical register driving electrode 42 and the second phase verticalregister driving electrode 43 is connected to electrodes of adjacentpixels on the same horizontal line, and therefore, the electrodes on thesame horizontal line are driven in synchronism. Since the third phasevertical register driving electrode 44 is connected to electrodes ofadjacent pixels on the same vertical line similarly as in the firstelectrode structure, the electrodes on the same vertical line are drivenin synchronism.

[0189] However, the second electrode structure is different from thefirst electrode structure in that the third phase vertical registerdriving electrode 44 is disposed along an edge portion of thecorresponding photo-diode 23 on the reading out gate 41 adjacent thephoto-diode 23 and a portion of the second phase vertical registerdriving electrode 43 which is worked in an elongated shape so as to beadjacent the edge portion of the photo-diode 23 overlies the reading outgate 41.

[0190] Accordingly, when a reading out pulse is applied to only one ofthe second phase vertical register driving electrode 43 and the thirdphase vertical register driving electrode 44, the barrier of the readingout gate 41 cannot be removed. In order to remove the barrier of thereading out gate 41 to allow charge accumulated in the photo-diode 23 tobe transferred to the vertical register 26, it is necessary to apply areading out pulse to the second phase vertical register drivingelectrode 43 and the third phase vertical register driving electrode 44simultaneously. In the following description, the electrode structureshown in FIG. 27 is referred to as AND type electrode structure.

[0191] An arbitrary mosaic arrangement with two stages of sensitivitycan be produced by using the OR type electrode structure and the ANDtype electrode structure described above in combination in one CCD imagesensor. For example, in order to implement a sensitivity mosaicarrangement of the color and sensitivity mosaic pattern P1 shown in FIG.5, the OR type electrode structure and the AND type electrode structureshould be used in such a combination as shown in FIG. 28.

[0192] As can be seen apparently from comparison between FIGS. 5 and 28,the AND type electrode structure is adopted for pixels having the lowsensitivity S0 from between the two sensitivity stages S0 and S1 whilethe OR type electrode structure is adopted for pixels of the highsensitivity S1. If the reading out pulse voltage is applied to thesecond phase vertical register driving electrodes 43 of the CCD imagesensor 4 formed from such a combination of the OR and AND type electrodestructures as just described, then charge reading out is performed onlywith the OR type pixels, but if the reading out pulse voltage is appliedto the second phase vertical register driving electrode 43 and the thirdphase vertical register driving electrode 44 simultaneously, then chargereading out is performed with both of the OR and AND type pixels, thatis, all pixels.

[0193] It is to be noted that, if the supplying timings of the pulsevoltage to the second phase vertical register driving electrode 43 andthe third phase vertical register driving electrode 44 are such thatboth of the second phase and the third phase are driven at the supplyingtiming of the charge reading out pulse voltage for the first time in (D)of FIG. 23 (or FIG. 24) from among the control timings shown in FIG. 23(or FIG. 24) and the supplying timing of the charge reading out pulsevoltage of (F) of FIG. 23 (or FIG. 24) whereas only the second phase isdriven at the supplying timing of the charge reading out pulse voltagefor the second time of (D) of FIG. 23 (or FIG. 24), then the pixels ofthe OR type electrode structure have the high sensitivity S1 while thepixels of the AND type electrode structure have the low sensitivity S0.

[0194] By a similar method, the other sensitivity mosaic arrangementshaving two stages of sensitivity can be produced. For example, in orderto implement the sensitivity mosaic pattern of the color and sensitivitymosaic pattern P2 shown in FIG. 6, the OR type and the AND type are usedin such a combination as shown in FIG. 29. In order to implement thesensitivity mosaic pattern of the color and sensitivity mosaic patternP3 shown in FIG. 7, the OR type and the AND type are used in such acombination as shown in FIG. 30. In order to implement the sensitivitymosaic pattern of the color and sensitivity mosaic pattern P4 shown inFIG. 8, the OR type and the AND type are used in such a combination asshown in FIG. 31. In order to implement the sensitivity mosaic patternof the color and sensitivity mosaic pattern P5 shown in FIG. 9, the ORtype and the AND type are used in such a combination as shown in FIG.32.

[0195] Now, a demosaic process of the image processing system includingthe image processing section 7 as a principal component is described.However, prior to the description of the demosaic process, a definitionof position coordinates of a pixel which is used in the descriptionhereinafter given is described with reference to FIG. 33.

[0196]FIG. 33 shows a coordinate system (x, y) indicating a position ofa pixel on an image. In particular, the left lower end of the image isrepresented by (0, 0) and the right upper end of the image isrepresented by (X_(max), Y_(max)). Pixels represented by □ in FIG. 33have a horizontal dimension and a vertical dimension of a length 1 andare arranged on a lattice. Accordingly, for example, the coordinates ofthe center of the pixel at the left lower end are (0.5, 0.5), and thecoordinates of the center of the pixel at the right upper end are(X_(max)−0.5, y_(max)−0.5). Further, image data whose phase is displacedvertically and horizontally by a half pixel from the pixels representedby □ (pixel data at a position represented by  in FIG. 33) is sometimesused, and, for example, the coordinates of image data whose phase isdisplaced vertically and horizontally by a half pixel from the pixel atthe left lower end are (1, 1).

[0197]FIG. 34 illustrates an outline of a first demosaic process of theimage processing system including the image processing section 7 as aprincipal component.

[0198] The first demosaic process includes, as seen in FIG. 34, asensitivity uniformization process for uniformizing the sensitivities ofpixels of a color and sensitivity mosaic image obtained by processing ofthe image pickup system without changing the colors of the pixels toproduce a color mosaic image, and a color correction process forrestoring RGB components of the pixels of a color and sensitivity mosaicimage M.

[0199] An outline of the first sensitivity uniformization process in thefirst demosaic process is described with reference to FIGS. 35 to 37.FIGS. 35 to 37 illustrate a pixel arrangement of a predetermined oneline of an image to be processed. X0 represents that the color componentis X (for example, R (red)) and the sensitivity is S0 from between thetwo stages of S0 and S1; X1 represents that the color component is X andthe sensitivity is S1 from between the two stages of S0 and S1; Y0represents that the color component is Y (for example, G (green)) andthe sensitivity is S0 from between the two stages of S0 and S1; and Y1represents that the color component is Y and the sensitivity is S1 frombetween the two stages of S0 and S1. Each pixel of the sensitivity S0measures the intensity of incoming light attenuated at a predeterminedratio while each pixel of the sensitivity S1 measures the intensity ofincoming light without any attenuation. Further, in FIGS. 35 to 37, theaxis of abscissa indicates the position of a pixel on a line, and thelength of a vertical bar indicates the pixel value of a correspondingpixel.

[0200] The first sensitivity uniformization process in the firstdemosaic process can be divided into processes of two different stages.FIG. 35 shows pixel values of pixels in a predetermined one line of acolor and sensitivity mosaic image before the first sensitivityuniformization process is performed. It is to be noted that a curve Xindicates an intensity distribution of the color X of the incominglight, and another curve Y indicates an intensity distribution of thecolor Y.

[0201] A threshold value θ_(H) indicates a saturation level of the CCDimage sensor 4, and when the intensity of the incoming light exceeds thethreshold value θ_(H), the intensity cannot be measured accurately andthe measurement value then is equal to the threshold value θ_(H).Another threshold value θ_(L) indicates a noise level of the CCD imagesensor 4, and also when the intensity of the incoming light is lowerthan the threshold value θ_(L), the intensity cannot be measuredaccurately and the measurement value then is equal to the thresholdvalue θ_(L).

[0202] A validity discrimination result is information representative ofwhether or not each pixel has successfully measured the intensity of theincoming light, that is, information representative of whether the pixelvalue of each pixel measured is valid (V) or invalid (I).

[0203] Through the first stage process of the first sensitivityuniformization process, the pixel values of the pixels of thesensitivity S0 are scaled using the relative ratio of the sensitivity S0to the sensitivity S1. The pixel values of the pixels of the sensitivityS1 are not scaled. FIG. 36 shows a result of application of the firststage process of the first sensitivity uniformization process. In thestate after the first stage process is performed, as seen in FIG. 36,the pixels whose validity discrimination result is valid have anoriginal light intensity restored by the scaling, but the pixels whosevalidity discrimination result is invalid do not have an originalrestored light intensity.

[0204] Therefore, in the second stage process of the first sensitivityuniformization process, the pixel value of each of those pixels whichare invalid is interpolated using the pixel values of those valid pixelsof the same color which neighbor with the pixel. FIG. 37 illustrates aresult of application of the second stage process of the firstsensitivity uniformization process. For example, the pixel of the colorY which is at the center of FIG. 37 and is invalid is interpolated inaccordance with an interpolation curve Y′ produced using the pixelvalues of those pixels of the color Y which neighbor with the pixel andare valid.

[0205] Subsequently, an outline of the second sensitivity uniformizationprocess of the first demosaic process is described with reference toFIGS. 35, 38 and 39. Also the second sensitivity uniformization processcan be divided into two stages of processes. The pixel values of pixelsin a predetermined one line of a color and sensitivity mosaic imagebefore the second sensitivity uniformization process is performed aresimilar to those in FIG. 35.

[0206] By the first stage process of the second sensitivityuniformization process, pixel values with regard to the sensitivity S0and pixel values with regard to the sensitivity S1 are estimated withoutchanging the color of each pixel. For example, for a pixel of thesensitivity S0 of the color X, the pixel value with regard to thesensitivity S0 is used at it is, and an estimated value with regard tothe sensitivity S1 is interpolated using the pixel values of thosepixels of the sensitivity S1 and the color X which are present in theneighborhood of the pixel. FIG. 38 shows a result of application of thefirst stage process of the second sensitivity uniformization process. Asshown in FIG. 38, after the first stage process is performed, each pixelhas a pixel value of sensitivity S0 or a pixel value of the sensitivityS1 of the original color.

[0207] By the second stage process of the second sensitivityuniformization process, for each pixel, the pixel values of thesensitivity S0 and the pixel values of the sensitivity S1 aresynthesized to uniform the sensitivity. FIG. 39 shows a result ofapplication of the second stage process of the second sensitivityuniformization process.

[0208]FIG. 40 shows an outline of the second demosaic process of theimage processing system which includes the image processing section 7 asa principal component.

[0209] The second demosaic process includes, as shown in FIG. 40, asensitivity uniformization process wherein the colors of pixels of acolor and sensitivity mosaic image obtained by the process of the imagepickup system are changed to colors optimum for sensitivityuniformization and the sensitivities are uniformized to produce a colormosaic image, and a color correction process for restoring RGBcomponents of pixels of the color and sensitivity mosaic image M.

[0210] An outline of the first sensitivity uniformization process of thesecond demosaic process is described with reference to FIGS. 35, 41 and42.

[0211] Also the first sensitivity uniformization process of the seconddemosaic process can be divided into two stages of processes. It isassumed that the pixel values of pixels in a predetermined one line of acolor and sensitivity mosaic image before the first sensitivityuniformization process is performed are similar to those in FIG. 35.

[0212] Through the first stage process of the first sensitivityuniformization process of the second demosaic process, the pixel valuesof the pixels of the sensitivity S0 are scaled using the relative ratioof the sensitivity S0 to the sensitivity S1. The pixel values of thepixels of the sensitivity S1 are not scaled. FIG. 41 shows a result ofapplication of the first stage process of the first sensitivityuniformization process. In the state after the first stage process isperformed, as seen in FIG. 41, the pixels whose validity discriminationresult is valid (V) have an original light intensity restored by thescaling, but the pixels whose validity discrimination result is invalid(I) do not have an original restored light intensity.

[0213] Therefore, in the second stage process of the first sensitivityuniformization process of the second demosaic process, the pixel valueof each of those pixels which are invalid is interpolated using thepixel values of those valid pixels, regardless colors thereof, whichneighbor with the pixel. FIG. 42 illustrates a result of application ofthe second stage process of the first sensitivity uniformizationprocess. For example, the pixel value of the pixel of the color Y whichis at the center of FIG. 41 and is invalid is interpolated in accordancewith an interpolation curve X′ produced using the pixel values of pixelsof the color X which neighbor with the pixel and are valid.

[0214] Now, an outline of the second sensitivity uniformization processof the second demosaic process is described with reference to FIGS. 35,43 and 44. Also the second sensitivity uniformization process of thesecond demosaic process can be divided into two stages of processes. Itis assumed that the pixel values of pixels on a predetermined one lineof a color and sensitivity mosaic image before the second sensitivityuniformization process is performed are similar to those in FIG. 35.

[0215] In the first stage process of the second sensitivityuniformization process of the second demosaic process, for each pixel,the pixel values of neighboring pixels which are positionedcomparatively near to the pixel irrespective of the color are used toestimate the pixel value with regard to the sensitivity S0 and the pixelvalue with regard to the sensitivity S1. For example, as an estimatedvalue of a pixel of the color X, where a pixel neighboring the pixel hasthe color Y, an estimated value with regard to the sensitivity S1 of thecolor Y and the pixel value with regard to the sensitivity S1 areinterpolated. FIG. 43 illustrates a result of application of the firststage process of the second sensitivity uniformization process. As shownin FIG. 43, after the first stage process is performed, each pixel hasthe pixel value with regard to the sensitivity S0 and the pixel valuewith regard to the sensitivity S1 of the original color because thecolor thereof has been changed to the color of the neighboring pixelirrespective of the original color.

[0216] In the second stage process of the second sensitivityuniformization process of the second demosaic process, for each pixel,the pixel value with regard to the sensitivity S0 and the pixel valuewith regard to the sensitivity S1 are synthesized to uniform thesensitivity. FIG. 44 shows a result of application of the second stageprocess of the second sensitivity uniformization process.

[0217] Now, a first example of a configuration of the image processingsection 7 which principally executes the first demosaic process isdescribed with reference to FIG. 45. It is assumed that, in thefollowing description, unless otherwise specified, the color andsensitivity mosaic image has the color and sensitivity mosaic pattern P2of FIG. 6, or in other words, in the color and sensitivity mosaic image,the color of each pixel is one of the three primary colors of R, G and Band the sensitivity is one of S0 and S1. However, the configuration andthe operation described below can be applied to another color andsensitivity mosaic image which includes three colors other than R, G andB or a further color and sensitivity mosaic image which includes fourcolors.

[0218] In the first example of a configuration of the image processingsection 7, a color and sensitivity mosaic image from the image pickupsystem is supplied to a sensitivity uniformization section 51. Colormosaic pattern information representative of a color mosaic arrangementof the color and sensitivity mosaic image is supplied to the sensitivityuniformization section 51 and a color interpolation section 52.Sensitivity mosaic pattern information representative of a sensitivitymosaic arrangement of the color and sensitivity mosaic image is suppliedto the sensitivity uniformization section 51.

[0219] The sensitivity uniformization section 51 performs a sensitivityuniformization process for the color and sensitivity mosaic image basedon the color mosaic pattern information and the sensitivity mosaicpattern information to produce a color mosaic image M wherein thesensitivities of the pixels are uniformized while the colors of thepixels are not changed, and outputs the color mosaic image M to thecolor interpolation section 52.

[0220] The color interpolation section 52 performs a color interpolationprocess, in which the color mosaic pattern information is used, for thecolor mosaic image M from the sensitivity uniformization section 51 toproduce output images R, G and B.

[0221] It is to be noted that the color mosaic pattern information isinformation representative of the types of the colors (in the presentcase, the colors of R, G and B) of the pixels of the color andsensitivity mosaic image, and information of a color component of eachof the pixels can be acquired using the position of the pixel as anindex.

[0222] The sensitivity mosaic pattern information is informationrepresentative of the types of the sensitivities (in the present case,S0 and S1) of the pixels of the color and sensitivity mosaic image, andinformation of the sensitivity of each of the pixels can be acquiredusing the position of the pixel as an index.

[0223]FIG. 46 shows a first example of the configuration of thesensitivity uniformization section 51. The first example of aconfiguration is an example of a configuration of the sensitivityuniformization section 51 which executes the first sensitivityuniformization process described with reference to FIGS. 35 to 37.

[0224] In the first example of the configuration of the sensitivityuniformization section 51, a color and sensitivity mosaic image from theimage pickup system is supplied to a sensitivity compensation section 61and a validity discrimination section 63. Color mosaic patterninformation is supplied to a missing interpolation section 64.Sensitivity mosaic pattern information is supplied to the sensitivitycompensation section 61 and the validity discrimination section 63.

[0225] The sensitivity compensation section 61 performs sensitivitycompensation for the color and sensitivity mosaic image based a relativesensitivity value S obtained from a relative sensitivity value LUT 62and outputs a resulting color and sensitivity mosaic image to themissing interpolation section 64. The relative sensitivity value LUT 62is a lookup table which outputs a relative sensitivity value S using thesensitivity of a pixel as an index.

[0226] The validity discrimination section 63 compares the pixel valueof each of the pixels of the color and sensitivity mosaic image with thethreshold value θ_(H) of the saturation level and the threshold valueθ_(L) of the noise level to discriminate the validity of the pixel valueand supplies a result of the discrimination as discriminationinformation to the missing interpolation section 64. In thediscrimination information, information representative of “valid” or“invalid” regarding the pixel value of each pixel is described.

[0227] The missing interpolation section 64 performs a missinginterpolation process for the sensitivity-compensated color andsensitivity mosaic image based on the discrimination information fromthe validity discrimination section 63 to produce a color mosaic image Mand outputs the color mosaic image M to the color interpolation section52 in the next stage.

[0228]FIG. 47 shows an example of a configuration of the colorinterpolation section 52. In the color interpolation section 52, thecolor mosaic image M from the sensitivity uniformization section 51 issupplied to a gradation conversion section 71. The color mosaic patterninformation is supplied to color difference image production sections 72and 73 and a luminance image production section 74.

[0229] The gradation conversion section 71 performs a gradationconversion process for the color mosaic image M and supplies a resultingmodulated color mosaic image Mg to the color difference image productionsections 72 and 73 and the luminance image production section 74. Forthe gradation conversion process, particularly conversion based on apower function of the power y or the like is used.

[0230] The color difference image production section 72 uses themodulated color mosaic image Mg to produce a color difference image Cwherein all pixels have a color difference C(=R−G) component andsupplies the color difference image C to the luminance image productionsection 74 and a color space conversion section 75. The color differenceimage production section 73 produces a color difference image D whereinall pixels have a color difference D(=B−G) component and supplies thecolor difference image D to the luminance image production section 74and the color space conversion section 75. The luminance imageproduction section 74 uses the modulated mosaic image Mg and the colordifference images C and D to produce a luminance image L and suppliesthe luminance image L to the color space conversion section 75.

[0231] The color space conversion section 75 performs a color spaceconversion process for the color difference images C and D and theluminance image L and supplies resulting modulated images (images ineach of which the pixels have an R, G or B component) to gradationreverse conversion sections 76 to 78.

[0232] The gradation reverse conversion section 76 raises the pixelvalues of the R components from the color space conversion section 75 tothe (1/γ)th power to perform reverse conversion to the gradationconversion by the gradation conversion section 71 to obtain an outputimage R. The gradation reverse conversion section 77 raises the pixelvalues of the G components from the color space conversion section 75 tothe (1/γ)th power to perform reverse conversion to the gradationconversion by the gradation conversion section 71 to obtain an outputimage G. The gradation reverse conversion section 78 raises the pixelvalues of the B components from the color space conversion section 75 tothe (1/γ)th power to perform reverse conversion to the gradationconversion by the gradation conversion section 71 to obtain an outputimage B.

[0233] It is to be noted that, where the color mosaic image M suppliedfrom the sensitivity uniformization section 51 has a Bayer arrangement,the color interpolation section 52 may execute a conventional colorinterpolation process, for example, using the related-art methoddisclosed in the official gazette of Japanese Patent Laid-Open No. Sho61-501424 and so forth.

[0234]FIG. 48 shows an example of a configuration of the colordifference image production section 72. In the color difference imageproduction section 72, the modulated color mosaic image Mg from thegradation conversion section 71 is supplied to smoothing sections 81 and82. Also the color mosaic pattern information is supplied to thesmoothing sections 81 and 82.

[0235] The smoothing section 81 uses, for each pixel, the pixel valuesof neighboring pixels having an R component to interpolate the Rcomponent of the pixel to produce a smoothed image R′ of the R componentand supplies the image R′ to a subtractor 83. The smoothing section 82uses, for each pixel, the pixel values of neighboring pixels having a Gcomponent to interpolate the G component of the pixel to produce asmoothed image G′ of the G component and supplies the image G′ to thesubtractor 83.

[0236] The subtractor 83 subtracts the pixel values of the pixels of thesmoothed image G′ of the G component from the smoothing section 82 fromthe pixel values of the corresponding pixels of the smoothed image R′ ofthe R component from the smoothing section 81 to produce a colordifference image C and supplies the color difference image C to thecolor space conversion section 75.

[0237] It is to be noted that also the color difference image productionsection 73 has a similar configuration.

[0238]FIG. 49 shows an example of a configuration of the luminance imageproduction section 74. A luminance calculation section 91 which composesthe luminance image production section 74 calculates a luminancecandidate value of each pixel based on the modulated color mosaic imageMg from the gradation conversion section 71, the color difference imageC from the color difference image production section 72, the colordifference image D from the color difference image production section 73and the color mosaic pattern information and outputs a luminancecandidate value image Lc formed from luminance pixel values of thepixels to a noise removal section 92.

[0239] The noise removal section 92 synthesizes a smoothing component(hereinafter described) with each of the pixel values (luminancecandidate values) of the luminance candidate value image Lc to removenoise from the luminance candidate value image Lc and outputs aresulting luminance image L to the color space conversion section 75.

[0240] Subsequently, the first demosaic process by the first example ofthe configuration of the image processing section 7 shown in FIG. 45 isdescribed with reference to a flow chart of FIG. 50.

[0241] At step S1, the sensitivity uniformization section 51 performs asensitivity uniformization process for the color and sensitivity mosaicimage based on the color mosaic pattern information and the sensitivitymosaic pattern information and outputs a resulting color mosaic image Mto the color interpolation section 52.

[0242] Details of the first sensitivity uniformization process by thefirst example of the configuration of the sensitivity uniformizationsection 51 shown in FIG. 46 are described with reference to a flow chartof FIG. 51.

[0243] At step S11, the sensitivity compensation section 61 performs asensitivity compensation process for the color and sensitivity mosaicimage inputted thereto and supplies the sensitivity-compensated colorand sensitivity mosaic image to the missing interpolation section 64.

[0244] Details of the sensitivity compensation process are describedwith reference to a flow chart of FIG. 52. At step S21, the sensitivitycompensation section 61 discriminates whether or not all pixels of thecolor and sensitivity mosaic image have been used as a noticed pixel. Ifthe sensitivity compensation section 61 discriminates that all pixelshave not been used as a noticed pixel, then the processing advances tostep S22. At step S22, the sensitivity compensation section 61determines one by one pixel as a noticed pixel beginning with the leftlowermost pixel and ending with the right uppermost pixel of the colorand sensitivity mosaic image.

[0245] At step S23, the sensitivity compensation section 61 refers tothe sensitivity mosaic pattern information to acquire the sensitivity(S0 or S1) of the noticed pixel and further refers to the relativesensitivity value LUT 62 to acquire the relative sensitivity value Scorresponding to the pixel of the noticed pixel.

[0246] At step S24, the sensitivity compensation section 61 divides thepixel value of the noticed pixel of the color and sensitivity mosaicimage by the relative sensitivity value S to compensate for thesensitivity of the pixel value. The sensitivity-compensated pixel valueis a pixel value of a sensitivity-compensated color and sensitivitymosaic image.

[0247] The processing returns to step S21 so that the processing atsteps S21 to S24 is repeated until it is discriminated at step S21 thatall pixels have been used as a noticed pixel. When it is discriminatedat step S21 that all pixels have been used as a noticed pixel, theprocessing returns to step S12 of FIG. 51.

[0248] At step S12, the validity discrimination section 63 performs avalidity discrimination process for the color and sensitivity mosaicimage to produce discrimination information representative of thevalidity of the pixel value of each pixel and supplies thediscrimination information to the missing interpolation section 64. Itis to be noted that the validity discrimination process at step S12 maybe executed in parallel to the sensitivity compensation process at stepS61.

[0249] Details of the validity discrimination process are described withreference to a flow chart of FIG. 53. At step S31, the validitydiscrimination section 63 discriminates whether or not all pixels of thecolor and sensitivity mosaic image have been used as a noticed pixel. Ifit is discriminated that all pixels have not been used as a noticedpixel, then the processing advances to step S32. At step S32, thevalidity discrimination section 63 determines one by one pixel as anoticed pixel beginning with the left lowermost pixel and ending withthe right uppermost pixel of the color and sensitivity mosaic image.

[0250] At step S33, the validity discrimination section 63 discriminateswhether or not the pixel value of the noticed pixel of the color andsensitivity mosaic image is within the range between the threshold valueθ_(L) of the noise level and the threshold value OH of the saturationlevel. If the validity discrimination section 63 discriminates that thepixel value is within the range between the threshold values, then theprocessing advances to step S34.

[0251] At step S34, the validity discrimination section 63 sets thediscrimination information of the noticed pixel as valid. The processingreturns to step S31.

[0252] If it is discriminated at step S33 that the pixel value of thenoticed pixel of the color and sensitivity mosaic image is not withinthe range between the threshold values, then the processing advances tostep S35. At step S35, the validity discrimination section 63discriminates whether or not the pixel value of the noticed pixel of thecolor and sensitivity mosaic image is equal to or higher than thethreshold level θ_(H) of the saturation level. If the validitydiscrimination section 63 discriminates that the pixel value is higherthan the threshold value OH of the saturation level, then the processingadvances to step S36.

[0253] At step S36, the validity discrimination section 63 refers to thesensitivity mosaic pattern information to discriminate whether or notthe noticed pixel has the sensitivity S0. If the validity discriminationsection 63 discriminates that the noticed pixel has the sensitivity S0,then the processing advances to step S34. If the validity discriminationsection 63 discriminates that the noticed pixel does not have thesensitivity S0, then the processing advances to step S37.

[0254] At step S37, the validity discrimination section 63 sets thediscrimination information of the noticed pixel as invalid. Theprocessing returns to step S31.

[0255] If it is discriminated at step S35 that the pixel value of thenoticed pixel of the color and sensitivity mosaic image is not equal toor higher than the threshold value θ_(H) of the saturation level, thenthe processing advances to step S38. At step S38, the validitydiscrimination section 63 refers to the sensitivity mosaic patterninformation to discriminate whether or not the noticed pixel has thesensitivity S1. If the validity discrimination section 63 discriminatesthat the noticed pixel has the sensitivity S1, then the processingadvances to step S34. However, if the validity discrimination section 63discriminates that the noticed pixel does not have the sensitivity S1,then the processing advances to step S37.

[0256] Thereafter, the processing at steps S31 to S38 is repeated untilit is discriminated at step S31 that all pixels have been used as anoticed pixel. When it is discriminated at step S31 that all pixels havebeen used as a noticed pixel, the processing returns to step S13 of FIG.51.

[0257] At step S13, the missing interpolation section 64 performs amissing interpolation process for the sensitivity-compensated color andsensitivity mosaic image based on the discrimination information fromthe validity discrimination section 63 and supplies a resulting colormosaic image M to the color interpolation section 52.

[0258] Details of the missing interpolation process are described withreference to a flow chart of FIG. 54. At step S41, the missinginterpolation section 64 discriminates whether or not all pixels of thesensitivity-compensated color and sensitivity mosaic image have beenused as a noticed pixel. If the missing interpolation section 64discriminates that all pixels have not been used as a noticed pixel,then the processing advances to step S42. At step S42, the missinginterpolation section 64 determines one by one pixel as a noticed pixelbeginning with the left lowermost pixel and ending with the rightuppermost pixel of the sensitivity-compensated color and sensitivitymosaic image.

[0259] At step S43, the missing interpolation section 64 discriminateswhether or not the discrimination information of the noticed pixel isinvalid. If the missing interpolation section 64 discriminates that thediscrimination information is invalid, then the processing advances tostep S44.

[0260] At step S44, the missing interpolation section 64 refers to thecolor mosaic pattern information to discriminate the type of the colorof the noticed pixel (in the present case, one of the colors of R, G andB), detect, from among neighboring pixels with the noticed pixel (forexample, in the present case, 5×5 pixels centered at the noticed pixel),those pixels which have the same color and whose discriminationinformation is valid, and extracts the pixel values of the detectedpixels (hereinafter referred to as reference pixels).

[0261] At step S45, the missing interpolation section 64 acquires anumber of filter coefficients set in advance corresponding to relativepositions of the reference pixels to the noticed pixel, the number beingequal to the number of the reference pixels. At step S46, the missinginterpolation section 64 multiplies the pixel values of the referencepixels by the corresponding filter coefficients and arithmeticallyoperates the sum total of the products. Further, the missinginterpolation section 64 divides the sum total of the products by thesum total of the used filter coefficients and determines the quotient asa pixel value of the noticed pixel of the color mosaic image M.

[0262] The processing returns to step S41 so that the processing atsteps S41 to 46 is repeated until it is discriminated at step S41 thatall pixels have been used as a noticed pixel. When it is discriminatedat step S41 that all pixels have been used as a noticed pixel, theprocessing returns to step S2 of FIG. 50.

[0263] At step S2, the color interpolation section 52 performs a colorinterpolation process for the color mosaic image M obtained by thesensitivity uniformization process at step S1 described above based onthe color mosaic pattern information to produce output images R, G andB.

[0264] Details of the color interpolation process are described withreference to a flow chart of FIG. 55. At step S51, the gradationconversion section 71 performs a gradation modulation process for thecolor mosaic image M (more particularly, raises the pixel values of themodulated color mosaic image Mg to the γth power) to produce a modulatedcolor mosaic image Mg and supplies the modulated color mosaic image Mgto the color difference image production sections 72 and 73 and theluminance image production section 74.

[0265] At step S52, the color difference image production section 72uses the modulated color mosaic image Mg from the gradation conversionsection 71 to produce a color difference image C and supplies the colordifference image C to the luminance image production section 74 and thecolor space conversion section 75. Meanwhile, the color difference imageproduction section 73 uses the modulated color mosaic image Mg from thegradation conversion section 71 to produce a color difference image Dand supplies the color difference image D to the luminance imageproduction section 74 and the color space conversion section 75.

[0266] The first process of the color difference image productionsection 72 producing a color difference image C is described withreference to a flow chart of FIG. 56. At step S61, the smoothingsections 81 and 82 discriminate whether or not all pixels of themodulated color mosaic image Mg have been used as a noticed pixel. Ifthe smoothing sections 81 and 82 discriminate that all pixels have notbeen used as a noticed pixel, then the processing advances to step S62.At step S62, the smoothing sections 81 and 82 determine one by one pixelas a noticed pixel beginning with the left lowermost pixel and endingwith the right uppermost pixel of the modulated color mosaic image Mg.

[0267] At step S63, the smoothing section 81 refers to the color mosaicpattern information to detect, from among neighboring pixels with thenoticed pixel (for example, 5×5 pixels centered at the noticed pixel),those pixels which have an R component, and extracts the pixel values ofthe detected pixels (hereinafter referred to as reference pixels).Meanwhile, also the smoothing section 82 similarly refers to the colormosaic pattern information to detect, from among neighboring pixels withthe noticed pixel, those pixels which have a G component, and extractsthe pixel values of the detected pixels.

[0268] At step S64, the smoothing section 81 acquires a number of filtercoefficients set in advance corresponding to relative positions of thereference pixels having an R component to the noticed pixel, the numberbeing equal to the number of the reference pixels. Meanwhile, also thesmoothing section 82 similarly acquires a number of filter coefficientsset in advance corresponding to relative positions of the referencepixels having a G component to the noticed pixel, the number being equalto the number of the reference pixels.

[0269] At step S65, the smoothing section 81 multiplies the pixel valuesof the reference pixels having an R component by the correspondingfilter coefficients and arithmetically operates the sum total of theproducts. Further, the smoothing section 81 divides the sum total of theproducts by the sum total of the used filter coefficients and determinesthe quotient as a pixel value corresponding to the noticed pixel of animage R′ which includes only smoothed R components. Meanwhile, also thesmoothing section 82 similarly multiplies the pixel values of thereference pixels having a G component by the corresponding filtercoefficients and arithmetically operates the sum total of the products.Further, the smoothing section 82 divides the sum total of the productsby the sum total of the used filter coefficients and determines thequotient as a pixel value corresponding to the noticed pixel of an imageG′ which includes only smoothed G components.

[0270] At step S66, the subtractor 83 subtracts the pixel valuecorresponding to the noticed pixel of the image R′ which includes onlysmoothed R components from the smoothing section 81 from the pixel valuecorresponding to the noticed pixel of the image G′ which includes onlysmoothed G components from the smoothing section 82 and determines thedifference as a pixel value corresponding to the noticed pixel of acolor difference image C.

[0271] The processing returns to step S61 so that the processing atsteps S61 to S66 is repeated until it is discriminated at step S61 thatall pixels have been used as a noticed pixel. When it is discriminatedat step S61 that all pixels have been used as a noticed pixel, theprocessing returns to step S53 of FIG. 55.

[0272] It is to be noted that, since the processing of the colordifference image production section 73 when it produces a colordifference image D is similar to the first process of the colordifference image production section 72 when it produces the colordifference image C described above, description of the processing isomitted.

[0273] At step S53, the luminance image production section 74 produces aluminance image L using the modulated mosaic image Mg and the colordifference signals C and D and supplies the luminance image L to thecolor space conversion section 75.

[0274] Details of the luminance image production process of theluminance image production section 74 are described with reference to aflow chart of FIG. 57. At step S71, the luminance calculation section 91discriminates whether or not all pixels of the modulated color mosaicimage Mg have been used as a noticed pixel. If the luminance calculationsection 91 discriminates that all pixels have not been used as a noticedpixel, then the processing advances to step S72. At step S72, theluminance calculation section 91 determines one by one pixel as anoticed pixel beginning with the left lowermost pixel and ending withthe right uppermost pixel of the modulated color mosaic image Mg.

[0275] At step S73, the luminance calculation section 91 refers to thecolor mosaic pattern information to discriminate the type of the colorof the noticed pixel (in the present case, one of the colors of R, G andB).

[0276] If it is discriminated at step S73 that the type of the color ofthe noticed pixel is R, then the processing advances to step S74. Atstep S74, the luminance calculation section 91 applies the modulatedcolor mosaic image Mg and the pixel values of the color differencesignals C and D corresponding to the noticed pixel to the followingexpression (1) to calculate the pixel value of a luminance candidateimage Lc corresponding to the noticed pixel:

Lc=3Mg−2C+D  (1)

[0277] If it is discriminated at step S73 that the type of the color ofthe noticed pixel is G, then the processing advances to step S75. Atstep S75, the luminance calculation section 91 applies the modulatedcolor mosaic image Mg and the pixel values of the color differencesignals C and D corresponding to the noticed pixel to the followingexpression (2) to calculate the pixel value of the luminance candidateimage Lc corresponding to the noticed pixel:

Lc=3Mg+C+D  (2)

[0278] If it is discriminated at step S73 that the type of the color ofthe noticed pixel is B, then the processing advances to step S76. Atstep S76, the luminance calculation section 91 applies the modulatedcolor mosaic image Mg and the pixel values Mg of the color differencesignals C and D corresponding to the noticed pixel to the followingexpression (3) to calculate the pixel value of the luminance candidateimage Lc corresponding to the noticed pixel:

Lc=3Mg+C−2D  (3)

[0279] It is to be noted that, in the expressions (1) to (3), Lc, Mg, Cand D represent the pixel values of the luminance candidate image Lc,modulated color mosaic image Mg, color difference signal C and colordifference image D corresponding to the noticed pixel, respectively.

[0280] The processing returns to step S71 so that the processing atsteps S71 to S76 is repeated until it is discriminated at step S71 thatall pixels have been used as a noticed pixel. When it is discriminatedat step S71 that all pixels have been used as a noticed pixel, theprocessing advances to step S77.

[0281] The luminance candidate image Lc produced by the processing atsteps S71 to S76 described above is supplied to the noise removalsection 92.

[0282] At step S77, the noise removal section 92 discriminates whetheror not all pixels of the modulated color mosaic image Mg have been usedas a noticed pixel. If the noise removal section 92 discriminates thatall pixels have not been used as a noticed pixel, then the processingadvances to step S78. At step S78, the noise removal section 92determines one by one pixel as a noticed pixel beginning with the leftlowermost pixel and ending with the right uppermost pixel of themodulated color mosaic image Mg.

[0283] At step S79, the noise removal section 92 applies the pixelvalues (luminance candidate values) of the pixels positioned upwardly,downwardly, leftwardly and rightwardly of the noticed pixel to thefollowing expression (4) to calculate a gradient ∇ corresponding to thenoticed pixel. It is to be noted that the gradient ∇ is a vector whosefactors are linear differential coefficients in the horizontal directionand the vertical direction of the image. Further, the pixel values(luminance candidate values) of the pixels positioned upwardly,downwardly, leftwardly and rightwardly of the noticed pixel arerepresented by Lc(U), Lc(D), Lc(L) and Lc(R), respectively.

gradient ∇=(Lc(R)−Lc(L), Lc(U)−Lc(D))  (4)

[0284] At step S80, the noise removal section 92 applies the pixelvalues (luminance candidate values) of the pixels positioned leftwardly,rightwardly, upwardly and downwardly of the noticed pixel to thefollowing expressions (5) and (6) to calculate a smoothed component Hhin the horizontal direction and a smoothed component Hv in the verticaldirection corresponding to the noticed pixel:

Hh=(Lc(L)+Lc(R))/2  (5)

Hv=(Lc(U)+Lc(D))/2  (6)

[0285] At step S81, the noise removal section 92 calculates a smoothingcontribution wh in the horizontal direction and a smoothing contributionwv in the vertical direction corresponding to the absolute value ∥∇∥ ofthe gradient ∇ corresponding to the noticed pixel calculated at stepS79.

[0286] More particularly, where the absolute value of the gradient ∇ ishigher than 0, the absolute value of the inner product of the normalizedgradient ∇/∥∇∥ and the vector (1, 0) is subtracted from 1 as given bythe following expression (7) to obtain the smoothing contribution wh inthe horizontal direction. Further, as given by the following expression(8), the absolute value of the inner product of the normalized gradient∇/∥∇∥ and the vector (0, 1) is subtracted from 1 to obtain the smoothingcontribution wv in the vertical direction:

wh=1−|(∇/∥∇∥, (1, 0))|  (7)

wv=1−|(∇/∥∇∥, (0, 1))|  (8)

[0287] Where the absolute value of the gradient ∇ is 0, the smoothingcontribution wh in the horizontal direction and the smoothingcontribution wv in the vertical direction are both set to 0.5.

[0288] At step S82, the noise removal section 92 uses the followingexpression (9) to calculate the pixel value (luminance value) of theluminance image L corresponding to the noticed pixel:

L=Lc+(wh·Hh+wv·Hv)/(wh+wv)  (9)

[0289] It is to be noted that Lc and L in the expression (9) representthe pixel values of the luminance candidate image Lc and the luminanceimage L corresponding to the noticed pixel.

[0290] The processing returns to step S77 so that the processing atsteps S77 to S82 is repeated until it is discriminated at step S77 thatall pixels have been used as a noticed pixel. When it is discriminatedat step S77 that all pixels have been used as a noticed pixel, theprocessing returns to step S54 of FIG. 55.

[0291] At step S54, the color space conversion section 75 performs acolor space conversion process for the color difference images C and Dand the luminance image L to produce modulated images in each of whicheach pixel has an R, G or B component and supplies the modulated imagesto the gradation reverse conversion sections 76 to 78, respectively.

[0292] Details of the color space conversion process are described withreference to a flow chart of FIG. 58. At step S91, the color spaceconversion section 75 discriminates whether or not all pixels of theluminance image L (which may alternatively be the color difference imageC or the color difference image D) have been used as a noticed pixel. Ifthe color space conversion section 75 discriminates that all pixels havenot been used as a noticed pixel, then the processing advances to stepS92. At step S92, the color space conversion section 75 determines oneby one pixel as a noticed pixel beginning with the left lowermost pixeland ending with the right uppermost pixel of the color and sensitivitymosaic image.

[0293] At step S93, the-color space conversion section 75 applies thepixel values of the luminance image L, color difference image C andcolor difference image D corresponding to the noticed pixel to thefollowing expressions (10), (11) and (12) to calculate the value Rg ofthe R component, the value Gg of the G component and the value Bg of theB component of the modulated images corresponding to the noticed pixel:$\begin{matrix}{{R\quad g} = {( {L + {2C} - D} )/3}} & (10) \\{{G\quad g} = {( {L - C - D} )/3}} & (11) \\{{B\quad g} = {( {L - C + {2D}} )/3}} & (12)\end{matrix}$

[0294] It is to be noted that, in the expressions (10) to (12), L, C andD are the pixel values of the luminance image L, color difference signalC and color difference image D corresponding to the noticed pixel,respectively.

[0295] The processing returns to step S91 so that the processing atsteps S91 to S93 is repeated until it is discriminated at step S91 thatall pixels have been used as a noticed pixel. When it is discriminatedat step S91 that all pixels have been used as a noticed pixel, theprocessing returns to step S55 of FIG. 55.

[0296] At step S55, the gradation reverse conversion section 76 performsa gradation reverse conversion process corresponding to the gradationconversion process at step S51 (more particularly, to raise pixel valuesto the 1/γth power) for the R component of each pixel of the modulatedimage supplied from the color space conversion section 75 to produce anoutput image R. Similarly, the gradation reverse conversion section 77performs a gradation reverse conversion process corresponding to thegradation conversion process at step S51 for the G component of eachpixel of the modulated image supplied from the color space conversionsection 75 to produce an output image G. The gradation reverseconversion section 78 performs a gradation reverse conversion processcorresponding to the gradation conversion process at step S51 for the Bcomponent of each pixel of the modulated image supplied from the colorspace conversion section 75 to produce an output image B. Through such acolor interpolation process as described above, the output images R, Gand BG are produced.

[0297] Description of the first demosaic process by the first example ofthe configuration of the sensitivity uniformization section 51 shown inFIG. 45 is ended thereby.

[0298] Now, a second example of the configuration of the sensitivityuniformization section 51 which can be used in place of the secondexample of the configuration of the sensitivity uniformization section51 shown in FIG. 46 is described with reference to FIG. 59.

[0299] The second example of the configuration is an example of theconfiguration wherein the second sensitivity uniformization process inthe first demosaic process described with reference to FIGS. 35, 38 and39 is executed by the sensitivity uniformization section 51.

[0300] It is assumed that, in the color and sensitivity mosaic imagedescribed below, the color of each pixel is one of the three primarycolors of R, G and B and the sensitivity is one of four stages S0, S1,S2 and S3 as in the color and sensitivity mosaic pattern P10 of FIG. 14or the color and sensitivity mosaic pattern P1 of FIG. 15. However, theconfiguration and the operation described below can be applied also toanother color and sensitivity mosaic image which includes three colorsother than R, G and B or a further color and sensitivity mosaic imagewhich includes four colors. Further, they can be applied also to a colorand sensitivity mosaic pattern wherein the sensitivity has two stages orthree stages.

[0301] In the second example of the configuration of the sensitivityuniformization section 51, a color and sensitivity mosaic image from theimage pickup system, color mosaic pattern information and sensitivitymosaic pattern information are supplied to interpolation sections 101-1to 101-4.

[0302] The interpolation section 101-1 performs an interpolation processof the sensitivity S0 without changing the color of each pixel of thecolor and sensitivity mosaic image and outputs an interpolation valuecorresponding to the resulting sensitivity S0 to an adder 102. Theinterpolation section 101-2 performs an interpolation process of thesensitivity S1 without changing the color of each pixel of the color andsensitivity mosaic image and outputs an interpolation valuecorresponding to the resulting sensitivity S to the adder 102. Theinterpolation section 101-3 performs an interpolation process of thesensitivity S2 without changing the color of each pixel of the color andsensitivity mosaic image and outputs an interpolation valuecorresponding to the resulting sensitivity S2 to the adder 102. Theinterpolation section 101-4 performs an interpolation process of thesensitivity S3 without changing the color of each pixel of the color andsensitivity mosaic image and outputs an interpolation valuecorresponding to the resulting sensitivity S3 to the adder 102.

[0303] The adder 102 adds, for each pixel, the sensitivities S0 to S3inputted thereto from the interpolation sections 101-1 to 101-4 andsupplies the sum as a pixel value of a color mosaic candidate image to asynthetic sensitivity compensation section 103.

[0304] The synthetic sensitivity compensation section 103 collates thepixel value of the color mosaic candidate image supplied thereto fromthe adder 102 with a synthetic sensitivity compensation LUT 104 toproduce a color mosaic image M wherein the resulting value is used as apixel value and supplies the color mosaic image M to the colorinterpolation section 52. The synthetic sensitivity compensation LUT 104is configured so as to acquire a pixel value of the color mosaic image Musing a pixel value of the color mosaic candidate image as an index.

[0305] The second sensitivity uniformization process in the firstdemosaic process by the second example of the configuration of thesensitivity uniformization section 51 shown in FIG. 59 is described withreference to a flow chart of FIG. 60.

[0306] At step S101, the interpolation sections 101-1 to 101-4discriminate whether or not all pixels of the color and sensitivitymosaic image have been used as a noticed pixel. If the interpolationsections 101-1 to 101-4 discriminate that all pixels have not been usedas a noticed pixel, then the processing advances to step S102. At stepS102, the interpolation sections 101-1 to 101-4 determine one by onepixel as a noticed pixel beginning with the left lowermost pixel andending with the right uppermost pixel of the color and sensitivitymosaic image.

[0307] At step S103, the interpolation sections 101-1 to 101-4 performan interpolation process without changing the color of each pixel of thecolor and sensitivity mosaic image to produce interpolation valuescorresponding to the sensitivities S0, S1, S2 and the sensitivity S3,respectively, and output the interpolation values to the adder 102.

[0308] The interpolation process for the sensitivity S0 by theinterpolation section 101-1 is described with reference to a flow chartof FIG. 61. At step 111, the interpolation section 101-1 detects thoseof pixels positioned in the neighborhood of the noticed pixel of thecolor and sensitivity mosaic image (for example, 5×5 pixels centered atthe noticed pixel) which have a color same as that of the noticed pixeland have the sensitivity S0, and extracts the pixel values of thedetected pixels (hereinafter referred to as reference pixels). At stepS112, the interpolation section 101-1 acquires a number of filtercoefficients set in advance corresponding to relative positions of thedetected reference pixels to the noticed pixel, the number being equalto the number of the reference pixels. At step S113, the interpolationsection 101-1 multiplies the pixel values of the reference pixels andthe corresponding filter coefficients and arithmetically operates thesum total of the products. Further, the interpolation section 101-1divides the sum total of the products by the sum total of the usedfilter coefficients and determines the quotient as an interpolationvalue corresponding to the sensitivity S0 of the noticed pixel. Theprocessing returns to step S60 of FIG. 60.

[0309] It is to be noted that, since the interpolation processes for thesensitivities S1 to S3 by the interpolation sections 101-2 and 101-3 aresimilar to the interpolation process for the sensitivity S0 by theinterpolation section 101-1 described above, description of theinterpolation processes is omitted.

[0310] At step S104, the adder 102 adds the interpolation values for thesensitivities S0 to S3 corresponding to the noticed pixel inputted fromthe interpolation sections 101-1 to 101-4 and supplies the sum as apixel value of a color mosaic candidate image corresponding to thenoticed pixel to the synthetic sensitivity compensation section 103.

[0311] At step S105, the synthetic sensitivity compensation section 103collates the pixel value of the color mosaic candidate image suppliedthereto from the adder 102 with the synthetic sensitivity compensationLUT 104 and determines a detected value as a pixel value of a colormosaic image M corresponding to the noticed pixel.

[0312] The processing returns to step S101 so that the processing atsteps S101 to S105 is repeated until it is discriminated at step S101that all pixels have been used as a noticed pixel. When it isdiscriminated at step S101 that all pixels have been used as a noticedpixel, the second sensitivity uniformization process of the firstdemosaic process is ended.

[0313] It is to be noted that, after the second sensitivityuniformization process, the color interpolation process describedhereinabove with reference to the flow chart of FIG. 55 is executed.

[0314] Now, a second process for producing a color difference image Cwhich can be executed by the color difference image production section72 in place of the first process (FIG. 56) for producing a colordifference image C described hereinabove is described with reference toa flow chart of FIG. 62.

[0315] At step S121, the smoothing sections 81 and 82 discriminatewhether or not all pixels of the modulated color mosaic image Mg havebeen used as a noticed pixel. If the smoothing sections 81 and 82discriminate that all pixels have not been used as a noticed pixel, thenthe processing advances to step S122. At step S122, the smoothingsections 81 and 82 determine one by one pixel as a noticed pixelbeginning with the left lowermost pixel and ending with the rightuppermost pixel of the modulated color mosaic image Mg.

[0316] At step S123, the smoothing section 81 arithmetically operates animage gradient vector g corresponding to the noticed pixel.

[0317] Details of the image gradient vector arithmetic operation processare described with reference to a flow chart of FIG. 63. In the imagegradient vector arithmetic operation process, only those of all pixelsof the color mosaic image Mg which have a single type of a color areused to arithmetically operate the image gradient vector g.

[0318] It is to be noted that, although a predetermined single type of acolor may be selected arbitrarily, for example, where the color mosaicpattern of the color mosaic image Mg has a Bayer arrangement, since thenumber of pixels having a G component is equal to twice that of pixelshaving an R component or pixels having a B component, the single type ofa color is reasonably set to G. Accordingly, the following descriptionproceeds assuming that the color mosaic pattern of the color mosaicimage Mg has a Bayer arrangement and that G is selected as thepredetermined single type of a color.

[0319] At step S141, the smoothing section 81 discriminates whether ornot the color of the noticed pixel is G. If the smoothing section 81discriminates that the color of the noticed pixel is G, then theprocessing advances to step S142. In this instance, the colors of thefour pixels positioned upwardly, downwardly, leftwardly and rightwardlyof the noticed pixel are not G, and the colors of the four pixelspositioned in the oblique directions from the noticed pixel are G.

[0320] At step S142, the smoothing section 81 interpolates the valuesG(U), G(D), G(L) and G(R) of G components corresponding to the fourpixels positioned upwardly, downwardly, leftwardly and rightwardly ofthe noticed pixel, respectively, by applying the pixel value G(LU) ofthe pixel neighboring leftwardly upwards of the noticed pixel and havinga G component, the pixel value G(LD) of the pixel neighboring leftwardlydownwards of the noticed pixel and having a G component, the pixel valueG(RU) of the pixel neighboring rightwardly upwards of the noticed pixeland having a G component and the pixel value G(RD) of the pixelneighboring rightwardly downwards of the noticed pixel and having a Gcomponent to the following expressions (13) to (16):

G(U)=(G(LU)+G(RU))/2  (13)

G(D)=(G(LD)+G(RD))/2  (14)

G(L)=(G(LU)+G(LD))/2  (15)

G(R)=(G(RU)+G(RD))/2  (16)

[0321] At step S143, the smoothing section 81 applies the values G(U),G(D), G(L) and G(R) of the G components corresponding to the four pixelspositioned upwardly, downwardly, leftwardly and rightwardly of thenoticed pixel to the following expressions (17) to (19) to calculate avector g′ and normalize the vector g′ in accordance with the followingexpression (20) to calculate a gradient vector g:

gh=G(R)−G(L)  (17)

gv=G(U)−G(D)  (18)

g′=(gh, gv)  (19)

g=G′/∥g′∥  (20)

[0322] It is to be noted that, if it is discriminated at step S141 thatthe color of the noticed pixel is not G, then the processing advances tostep S144. In this instance, the colors of the four pixels positionedupwardly, downwardly, leftwardly and rightwardly of the noticed pixelare G.

[0323] At step S144, the smoothing section 81 acquires the pixel valuesof the four pixels positioned upwardly, downwardly, leftwardly andrightwardly of the noticed pixel and substitutes them into the valuesG(U), G(D), G(L) and G(R), respectively.

[0324] The image gradient vector g corresponding to the noticed pixel isarithmetically operated in such a manner as described above. It is to benoted that, also where the color mosaic pattern of the color mosaicimage Mg does not have a Bayer arrangement, a similar process can beapplied to arithmetically operate the image gradient vector g.

[0325] The processing returns to step S124 of FIG. 62.

[0326] At step S124, the smoothing section 81 refers to the color mosaicpattern information to detect those of pixels neighboring with thenoticed pixel (for example, 5×5 pixels centered at the noticed pixel)which have an R component, and extracts the pixel values of the detectedpixels (hereinafter referred to as reference pixels). Meanwhile, alsothe smoothing section 82 similarly refers to the color mosaic patterninformation to detect those of pixels neighboring with the noticed pixelwhich have a G component, and extracts the pixel values of the detectedpixels.

[0327] At step S125, the smoothing section 81 calculates the positionvectors n from the noticed pixel to the reference pixels which have an Rcomponent and normalizes them. Meanwhile, also the smoothing section 82similarly calculates the position vectors n from the noticed pixel tothe reference pixels which have a G component and normalizes them.

[0328] At step S126, as shown in the following expression (21), thesmoothing section 81 divides, for each of the reference pixels having anR component, the absolute value of an inner product of the gradientvector g of the noticed pixel and the position vector n from 1 andarithmetically operates the difference to the ρth power to calculate asignificance ω of the reference pixel. Meanwhile, also the smoothingsection 82 similarly calculates a significance ω for each of thereference pixels having a G component. Here, ρ is a constant foradjusting the sharpness of direction selection and is set in advance.

ω=(1−(n, g)|)^(ρ)  (21)

[0329] At step S127, the smoothing section 81 acquires a number offilter coefficients set in advance corresponding to relative positionsof the reference pixels having an R component to the noticed pixel, thenumber being equal to the number of the reference pixels. Meanwhile,also the smoothing section 82 similarly acquires a number of filtercoefficients set in advance corresponding to relative positions of thereference pixels having a G component to the noticed pixel, the numberbeing equal to the number of the reference pixels.

[0330] At step S128, the smoothing section 81 multiplies the pixelvalues of the reference pixels having an R component by thecorresponding filter coefficients and significances ω and arithmeticallyoperates the sum total of the products. Further, the smoothing section81 multiplies the filter coefficients and the significances ωcorresponding to the reference pixels and arithmetically operates thesum total of the products. Meanwhile, also the smoothing section 82similarly multiplies the pixel values of the reference pixels having a Gcomponent by the corresponding filter coefficients and significances ωand arithmetically operates the sum total of the products. Further, thesmoothing section 82 multiplies the filter coefficients and thesignificances ω corresponding to the reference pixels and arithmeticallyoperates the sum total of the products.

[0331] At step S129, the smoothing section 81 divides the sum total ofthe products of the pixel values of the reference pixels having an Rcomponent and the corresponding filter coefficients and significances ωby the sum total of the products of the filter coefficients and thesignificances ω corresponding to the reference pixels calculated at stepS128 and determines the quotient as a pixel value corresponding to thenoticed pixel of the image R′ which includes only smoothed R components.Meanwhile, also the smoothing section 82 divides the sum total of theproducts of the pixel values of the reference pixels having a Gcomponent and the corresponding filter coefficients and significances ωby the sum total of the products of the filter coefficients and thesignificances ω corresponding to the reference pixels calculated at stepS128 and determines the quotient as a pixel value corresponding to thenoticed pixel of the image G′ which includes only smoothed G components.

[0332] At step S130, the subtractor 83 subtracts the pixel valuecorresponding to the noticed pixel of the image G′, which only includessmoothed G components, from the smoothing section 82 from the pixelvalue corresponding to the noticed pixel of the image R′, which onlyincludes smoothed R components, from the smoothing section 81, anddetermines the difference as a pixel value of the noticed pixel of thecolor difference image C.

[0333] The processing returns to step S121 so that the processing atsteps S121 to 130 is repeated until it is discriminated at step S121that all pixels have been used as a noticed pixel. When it isdiscriminated at step S121 that all pixels have been used as a noticedpixel, the color difference image production process is ended and theprocessing returns to step S53 of FIG. 55.

[0334] It is to be noted that, since the process of the color differenceimage production section 73 when it produces a color difference image Dis similar to the second process of the color difference imageproduction section 72 when it produces the color difference image Cdescribed above, description of it is omitted.

[0335] In the second process for producing a color difference image C,since a contour of an object in an image is detected and smoothing isexecuted in parallel to the contour, occurrence of a color moire effectcan be suppressed when compared with that in the first process forproducing the color difference image C.

[0336] Subsequently, a second example of a configuration of the imageprocessing section 7 which principally executes the second demosaicprocess is described with reference to FIG. 64. In the second example ofthe configuration of the image processing section 7, a color andsensitivity mosaic image from the image pickup system, color mosaicpattern information representative of a color mosaic arrangement of thecolor and sensitivity mosaic image and sensitivity mosaic patterninformation representative of a sensitivity mosaic arrangement of thecolor and sensitivity mosaic image are supplied to a sensitivityuniformization section 111.

[0337] The sensitivity uniformization section 111 performs a sensitivityuniformization process for the color and sensitivity mosaic image basedon the color mosaic pattern information and the sensitivity mosaicinformation and outputs a resulting color mosaic image M having auniformized sensitivity to the color interpolation section 52. It is tobe noted, however, that, since the color mosaic arrangement of theresulting color mosaic image M is not necessarily same as the colormosaic arrangement of the original color and sensitivity mosaic image,the sensitivity uniformization section 111 updates the color mosaicpattern information and supplies it to a color interpolation section112.

[0338] The color interpolation section 112 performs, similarly to thecolor interpolation section 52 of FIG. 45, a color interpolationprocess, in which the color mosaic pattern information is used, for thecolor mosaic image M from the sensitivity uniformization section 111 toproduce output images R, G and B.

[0339]FIG. 65 shows a first example of a configuration of thesensitivity uniformization section 111. The first example of theconfiguration is an example of a configuration of the sensitivityuniformization section 111 which executes the first sensitivityuniformization process in the second demosaic process describedhereinabove with reference to FIGS. 35, 41 and 42.

[0340] In the first example of the configuration of the sensitivityuniformization section 111, a color and sensitivity mosaic image fromthe image pickup system is supplied to a sensitivity compensationsection 121 and a validity discrimination section 123. Color mosaicpattern information is supplied to a missing interpolation section 124.Sensitivity mosaic pattern information is supplied to the sensitivitycompensation section 121 and the validity discrimination section 123.

[0341] The sensitivity compensation section 121 performs sensitivitycompensation for the color and sensitivity mosaic image based on arelative sensitivity value S obtained from a relative sensitivity valueLUT 122 and outputs the resulting color and sensitivity mosaic image tothe missing interpolation section 124. The relative sensitivity valueLUT 122 is a lookup table which outputs a relative sensitivity value Susing a sensitivity of a pixel as an index.

[0342] The validity discrimination section 123 compares the pixel valueof each of the pixels of the color and sensitivity mosaic image with thethreshold value θ_(H) of the saturation level and the threshold valueθ_(L) of the noise level to discriminate the validity of the pixel valueand supplies a result of the discrimination as discriminationinformation to the missing interpolation section 124. In thediscrimination information, information representative of “valid” or“invalid” regarding the pixel value of each pixel is described.

[0343] The missing interpolation section 124 uses, based on thediscrimination information from the validity discrimination section 123,the pixel values of those pixels from among all pixels of thesensitivity-compensated color and sensitivity mosaic image whosediscrimination information is valid as they are, but uses, for each ofthose pixels whose discrimination information is invalid, the pixelvalues of those pixels having a color which is included most in thesensitivity-compensated color and sensitivity mosaic image tointerpolate the pixel value of the color component. Use of the pixelvalues of those pixels having a color which is included most in thismanner facilitates restoration of a high frequency component. Further,the missing interpolation section 124 updates the color mosaic patterninformation corresponding to the color mosaic arrangement of theproduced color mosaic image M and outputs the updated color mosaicpattern information to the color interpolation section 112.

[0344] Now, a second demosaic process executed principally by the secondexample of the configuration of the image processing section 7 shown inFIG. 64 is described. However, most part of the second demosaic processis similar to that of the first demosaic process described hereinabove.Therefore, a process different from that of the first demosaic processdescribed hereinabove, that is, a missing interpolation process of themissing interpolation section 124 which composes the sensitivityuniformization section 111 is described with reference to a flow chartof FIG. 66. In the following description, it is assumed that the numberof pixels having a G component is greatest in the color and sensitivitymosaic image. However, a similar process can be applied similarly alsowhere the number of pixels having any other color component is greatest.

[0345] At step S151, the missing interpolation section 124 discriminateswhether or not all pixels of the sensitivity-compensated color andsensitivity mosaic image have been used as a noticed pixel. If themissing interpolation section 124 discriminates that all pixels have notbeen used as a noticed pixel, then the processing advances to step S152.At step S152, the missing interpolation section 124 determines one byone pixel as a noticed pixel beginning with the left lowermost pixel andending with the right uppermost pixel of the sensitivity-compensatedcolor and sensitivity mosaic image.

[0346] At step S153, the missing interpolation section 124 discriminateswhether or not the discrimination information of the noticed pixel isinvalid. If the missing interpolation section 124 discriminates that thediscrimination information is invalid, then the processing advances tostep S154.

[0347] At step S154, the missing interpolation section 124 refers to thecolor mosaic pattern information to detect those pixels neighboring withthe noticed pixel (for example, 5×5 pixels centered at the noticedpixel) which have a G component and whose discrimination information isvalid, and extracts the pixel values of the detected pixels (hereinafterreferred to as reference pixels). Further, the missing interpolationsection 124 acquires a number of filter coefficients set in advancecorresponding to relative positions of the reference pixels to thenoticed pixel, the number being equal to the number of the referencepixels. Furthermore, the missing interpolation section 124 multipliesthe pixel values of the reference pixels and the corresponding filtercoefficients and arithmetically operates the sum total of the products.Further, the missing interpolation section 124 divides the sum total ofthe products by the sum total of the used filter coefficients anddetermines the quotient as a pixel value of the noticed pixel of thecolor mosaic image M.

[0348] At step S155, the missing interpolation section 124 updates thecolor of the noticed pixel in the color mosaic pattern information to G.

[0349] It is to be noted that, if it is discriminated at step S153 thatthe discrimination information of the noticed pixel is not invalid, thenthe processes at steps S154 and S155 are skipped.

[0350] The processing returns to step S151 so that the processing atsteps S151 to 155 is repeated until it is discriminated at step S151that all pixels have been used as a noticed pixel. When it isdiscriminated at step S151 that all pixels have been used as a noticedpixel, the missing interpolation process is ended and the color mosaicimage M obtained and the updated color mosaic pattern information aresupplied to the color interpolation section 112 in the following stage.

[0351] Now, a second example of a configuration of the sensitivityuniformization section 111 which can be used in place of the firstexample of the configuration of the sensitivity uniformization section111 shown in FIG. 65 is described with reference to FIG. 67.

[0352] The second example of the configuration is an example of aconfiguration for allowing the sensitivity uniformization section 111 toexecute the second sensitivity uniformization process of the seconddemosaic process described hereinabove with reference to FIGS. 35, 43and 44.

[0353] The following description proceeds assuming that, in the colorand sensitivity mosaic image, the color of each pixel is one of thethree primary colors of R, G and B as in the color and sensitivitymosaic pattern P10 of FIG. 14 or the color and sensitivity mosaicpattern P1 of FIG. 15 and the sensitivity is one of sensitivities offour stages of S0, S1, S2 and S3. However, the configuration and theoperation described below can be applied also to another color andsensitivity mosaic image which includes three colors other than R, G andB or a further color and sensitivity mosaic image which includes fourcolors. Furthermore, they can, be applied also to a color andsensitivity mosaic pattern wherein the number of stages of sensitivityis two or three.

[0354] In the second example of the configuration of the sensitivityuniformization section 111, a color and sensitivity mosaic image fromthe image pickup system, color mosaic pattern information andsensitivity mosaic pattern information are supplied to interpolationsections 132-1 to 132-4. The color mosaic pattern information issupplied also to an interpolation color determination section 131.

[0355] The interpolation color determination section 131 designates thecolor (interpolation color) of interpolation values to be interpolatedby the interpolation sections 132-1 to 132-3 based on the color mosaicpattern information. Further, the interpolation color determinationsection 131 updates the color mosaic pattern information in accordancewith determination of the interpolation colors.

[0356] The interpolation section 131-1 performs an interpolation processof the sensitivity S0 for the color and sensitivity mosaic image inaccordance with the designation of an interpolation color from theinterpolation color determination section 131 and outputs a resultinginterpolation value corresponding to the sensitivity S0 to an adder 133.The interpolation section 131-2 performs an interpolation process of thesensitivity S1 for the color and sensitivity mosaic image in accordancewith the designation of the interpolation color from the interpolationcolor determination section 131 and outputs a resulting interpolationvalue corresponding to the sensitivity S1 to the adder 133. Theinterpolation section 131-3 performs an interpolation process of thesensitivity S2 for the color and sensitivity mosaic image in accordancewith the designation of the interpolation color from the interpolationcolor determination section 131 and outputs a resulting interpolationvalue corresponding to the sensitivity S2 to the adder 133. Theinterpolation section 131-4 performs an interpolation process of thesensitivity S3 for the color and sensitivity mosaic image in accordancewith the designation of the interpolation color from the interpolationcolor determination section 131 and outputs a resulting interpolationvalue corresponding to the sensitivity S3 to the adder 133.

[0357] The adder 133 adds the interpolation values of the sensitivitiesS0 to S3 inputted thereto from the interpolation sections 132-1 to 132-4for each pixel and supplies the sum as a pixel value of a color mosaiccandidate image to a synthetic sensitivity compensation section 134.

[0358] The synthetic sensitivity compensation section 134 collates thepixel value of the color mosaic candidate image supplied thereto fromthe adder 133 with a synthetic sensitivity compensation LUT 135 andproduces and supplies a color mosaic image wherein the resulting valueis used as a pixel value to the color interpolation section 112. Thesynthetic sensitivity compensation LUT 135 allows a pixel value of thecolor and sensitivity mosaic image M using a pixel value of the colormosaic candidate image as an index.

[0359] A second sensitivity uniformization process in the seconddemosaic process by the second example of the configuration of thesensitivity uniformization section 111 shown in FIG. 67 is describedwith reference to a flow chart of FIG. 68.

[0360] At step S161, the interpolation sections 132-1 to 132-4discriminate whether or not all pixels of the color and sensitivitymosaic image have been used as a noticed pixel. If the interpolationsections 132-1 to 132-4 discriminate that all pixels have not been usedas a noticed pixel, then the processing advances to step S162. At stepS162, the interpolation sections 132-1 to 132-4 determine one by onepixel as a noticed pixel beginning with the left lowermost pixel andending with the right uppermost pixel of the color and sensitivitymosaic image.

[0361] At step S163, the interpolation color determination section 131executes an interpolation color determination process based on the colormosaic pattern information and issues a notification of a resultinginterpolation color of the noticed pixel to the interpolation sections132-1 to 132-4.

[0362] Details of the interpolation color determination process of theinterpolation color determination section 131 are described withreference to a flow chart of FIG. 69. It is to be noted that the objectof the interpolation color determination process is to interpolate thepixel value of the noticed pixel using pixels comparatively neighboringwith the noticed pixel and it is assumed that the color mosaicarrangement of the color and sensitivity mosaic image has a Bayerarrangement.

[0363] At step S171, the interpolation color determination section 131refers to the color mosaic pattern information to discriminate the colorof the noticed pixel.

[0364] If it is discriminated at step S171 that the color of the noticedpixel is G, then the processing advances to step S172. In this instance,also the colors of the four pixels neighboring in the oblique directionswith the noticed pixel are G. At step S172, the interpolation colordetermination section 131 determines the interpolation color of thenoticed pixel as G and issues a notification of this to theinterpolation sections 132-1 to 132-4. Further, the interpolation colordetermination section 131 updates the color mosaic pattern informationcorresponding to the noticed pixel to G.

[0365] If it is discriminated at step S171 that the color of the noticedpixel is R, then the processing advances to step S173. In this instance,the colors of the four pixels neighboring in the oblique directions withthe noticed pixel are B. At step S173, the interpolation colordetermination section 131 determines the interpolation color of thenoticed pixel as B and issues a notification of this to theinterpolation sections 132-1 to 132-4. Further, the interpolation colordetermination section 131 updates the color mosaic pattern informationcorresponding to the noticed pixel to G.

[0366] If it is discriminated at step S171 that the color of the noticedpixel is B, then the processing advances to step S174. In this instance,also the colors of the four pixels neighboring in the oblique directionswith the noticed pixel are R. At step S174, the interpolation colordetermination section 131 determines the interpolation color of thenoticed pixel as R and issues a notification of this to theinterpolation sections 132-1 to 132-4. Further, the interpolation colordetermination section 131 updates the color mosaic pattern informationcorresponding to the noticed pixel to R.

[0367] With the interpolation color determination process describedabove, the interpolation color of the noticed pixel is designated sothat R and B of the color and sensitivity mosaic image whose colormosaic arrangement is a Bayer arrangement are exchanged for each other.Therefore, also the updated color mosaic pattern information maintainsthe Bayer arrangement.

[0368] The processing returns to step S164 of FIG. 68. At step S164, theinterpolation sections 132-1 to 132-4 individually perform aninterpolation process for the color and sensitivity mosaic image inaccordance with the designation of the interpolation color from theinterpolation color determination section 131 to produce aninterpolation value corresponding to the sensitivity S0, S1, S2 or S3and outputs the interpolation value to the adder 133.

[0369] More particularly, for example, the interpolation section 132-1detects, from among pixels positioned in the neighborhood of the noticedpixel of the color and sensitivity mosaic image (for example, from among5×5 pixels centered at the noticed pixel), those pixels which have thecolor designated from the interpolation color determination section 131and whose sensitivity is S0, and extracts the pixel values of thedetected pixels (hereinafter referred to as reference pixels). Further,the interpolation section 132-1 acquires a number of filter coefficientsset in advance corresponding to relative positions of the detectedreference pixels to the noticed pixel, the number being equal to thenumber of the reference pixels. Furthermore, the interpolation section132-1 multiplies the pixel values of the reference pixels and thecorresponding filter coefficients and arithmetically operates the sumtotal of the products. Further, the interpolation section 132-1 dividesthe sum total of the products by the sum total of the used filtercoefficients and determines the quotient as an interpolation valuecorresponding to the sensitivity S0 of the noticed pixel.

[0370] It is to be noted that the interpolation processes for thesensitivities S1 to S3 by the interpolation sections 132-2 to 132-3 aresimilar to the interpolation process for the sensitivity S0 by theinterpolation section 132-1, and therefore, description of it isomitted.

[0371] At step S165, the adder 133 adds the interpolation values for thesensitivities S0 to S3 corresponding to the noticed pixel inputtedtherefrom from the interpolation sections 132-1 to 132-4 and suppliesthe sum as a pixel value of the color mosaic candidate imagecorresponding to the noticed pixel to the synthetic sensitivitycompensation section 133.

[0372] At step S166, the synthetic sensitivity compensation section 134collates the pixel value of the color mosaic candidate image suppliedthereto from the adder 133 with the synthetic sensitivity compensationLUT 135 and determines a resulting value as a pixel value of the colormosaic image M corresponding to the noticed pixel.

[0373] The processing returns to step S161 so that the processing atsteps S161 to 166 is repeated until it is discriminated at step S161that all pixels have been used as a noticed pixel. When it isdiscriminated at step S161 that all pixels have been used as a noticedpixel, the second sensitivity uniformization process in the seconddemosaic process is ended.

[0374] It is to be noted that, although a color interpolation process isperformed by the color interpolation section 112 for the color mosaicimage M obtained by the second sensitivity uniformization process of thesecond demosaic process, since the process is similar to the colorinterpolation process described hereinabove with reference to the flowchart of FIG. 55, description of it is omitted.

[0375]FIG. 70 illustrates an outline of a third demosaic process of theimage processing system which includes the image processing section 7 asa principal component.

[0376] The third demosaic process includes, as seen in FIG. 70, aby-sensitivity-basis color interpolation process wherein RGB componentsof pixels of a color and sensitivity mosaic image obtained by processingof the image pickup section are interpolated without changing thesensitivities of the pixels to produce a sensitivity mosaic image MsRfor an R component, a sensitivity mosaic image MsG for a G component anda sensitivity mosaic image MsB for a B component, and a sensitivityuniformization process for uniformizing the sensitivities of thesensitivity mosaic image for an R component, the sensitivity mosaicimage for a G component and the sensitivity mosaic image for a Bcomponent to produce output images R, G and B, respectively.

[0377] The by-sensitivity-basis color interpolation process of the thirddemosaic process includes an extraction process for extracting onlythose pixels which have the same sensitivity from the color andsensitivity mosaic image, a color interpolation process forinterpolating the pixel values of the RGB components of the pixelsextracted by the extraction process, and an insertion process forsynthesizing the pixel values interpolated by the color interpolationprocess for each of the RGB components to produce sensitivity mosaicimages.

[0378] For example, in the extraction process, only the pixels whichhave the sensitivity S1 are extracted from the color and sensitivitymosaic image to produce a color mosaic image McS1 wherein the pixels aredisposed in a checkered manner. In the color interpolation process, animage Rs1 wherein the pixels which have the sensitivity S1 and have an Rcomponent are disposed in a checkered manner, another image Gs1 whereinthe pixels which have the sensitivity S1 and have a G component aredisposed in a checkered manner and a further image Bs1 wherein thepixels which have the sensitivity S1 and have a B component are disposedin a checkered manner are produced from the color mosaic image McS1.

[0379] For example, in the insertion process, an image RS0 and anotherimage RS1 produced by the color interpolation process are combined toproduce a sensitivity mosaic image MsR.

[0380] Subsequently, a third example of a configuration of the imageprocessing section 7 which principally executes the third demosaicprocess is described with reference to FIG. 73.

[0381] In the third example of the configuration of the image processingsection 7, a color and sensitivity mosaic image from the image pickupsystem is supplied to a by-sensitivity-basis color interpolation section151. Color mosaic pattern information representative of a color mosaicarrangement of the color and sensitivity mosaic image is supplied to theby-sensitivity-basis color interpolation section 151. Sensitivity mosaicpattern information representative of a sensitivity mosaic arrangementof the color and sensitivity mosaic image is supplied to theby-sensitivity-basis color interpolation section 151 and sensitivityuniformization sections 152 to 154.

[0382] It is to be noted that, in the following description, unlessotherwise specified, the color and sensitivity mosaic image has thecolor and sensitivity mosaic pattern P3 of FIG. 7. In particular, eachpixel has a color which is one of the three primary colors of R, G and Band has a sensitivity of one of S0 and S1 Further, where attention ispaid to only the pixels of the sensitivity S0 irrespective of the color,they are arranged in a checkered manner. Similarly, the pixels of thesensitivity S1 are arranged in a checkered manner.

[0383] However, the configuration and the operation described below canbe applied also to another color and sensitivity mosaic image havingthree colors other than R, G and B or a further color and sensitivitymosaic image which has four colors.

[0384] The by-sensitivity-basis color interpolation section 151 performsa by-sensitivity-basis color interpolation process for the color andsensitivity mosaic image and supplies resulting sensitivity mosaic imageMsR for an R component, sensitivity mosaic image MsG for a G componentand sensitivity mosaic image MsB for a B component to corresponding onesof the sensitivity uniformization sections 152 to 154, respectively.

[0385] The sensitivity uniformization section 152 performs a sensitivityuniformization process for the sensitivity mosaic image MsR for an Rcomponent to produce an output image R. The sensitivity uniformizationsection 153 performs a sensitivity uniformization process for thesensitivity mosaic image MsG for a G component to produce an outputimage G. The sensitivity uniformization section 154 performs asensitivity uniformization process for the sensitivity mosaic image MsBfor a B component to produce an output image B.

[0386]FIG. 74 shows an example of a configuration of theby-sensitivity-basis color interpolation section 151. In theby-sensitivity-basis color interpolation section 151, the color andsensitivity mosaic image, color mosaic pattern information andsensitivity mosaic pattern information are supplied to an extractionsection 161.

[0387] The extraction section 161 performs an extraction process of thesensitivity Si (in the present case, i=0 or 1) for the color andsensitivity mosaic image and supplies a resulting color mosaic imageMcSi which includes pixels of the sensitivity Si to a colorinterpolation section 162. It is to be noted that the color mosaic imageMcSi is an image represented using an st coordinate system differentfrom the xy coordinate system of the original color and sensitivitymosaic image (details are hereinafter described with reference to FIGS.78 and 79). Further, the extraction section 161 produces color mosaicpattern information of the sensitivity Si representative of a colormosaic arrangement of the color mosaic image McSi and supplies the colormosaic pattern information to the color interpolation section 162.Furthermore, the extraction section 161 produces original positioninformation of the sensitivity Si which has a positional relationshipbetween the color mosaic image McSi and the original color andsensitivity mosaic image and supplies the original position informationof the sensitivity Si to insertion sections 163 to 165.

[0388] The color interpolation section 162 interpolates RGB componentsof all pixels of the color mosaic image McSi from the extraction section161 and supplies resulting images Rsi, Gsi and Bsi to the correspondinginsertion sections 163 to 165, respectively. The image Rsi is an imagecomposed of pixel values of R components corresponding to the pixels ofthe color mosaic image McSi. The image Gsi is an image composed of pixelvalues of G components corresponding to the pixels of the color mosaicimage McSi. The image Bsi is an image composed of pixel values of Bcomponents corresponding to the pixels of the color mosaic image McSi.Further, the images Rsi, Gsi and Bsi are represented using a coordinatesystem same as that of the color mosaic image McSi. It is to be notedthat the color interpolation section 162 is configured in a similarmanner as in the example of the configuration of the color interpolationsection 52 shown in FIG. 47.

[0389] The insertion section 163 combines a number of images Rsi of an Rcomponent equal to the number of kinds of sensitivities supplied fromthe color interpolation section 162 based on the original positioninformation of the sensitivity Si supplied from the extraction section161 to produce a sensitivity mosaic image MsR, and supplies thesensitivity mosaic image MsR to the sensitivity uniformization section152. The insertion section 164 combines a number of images Gsi of a Gcomponent equal to the number of kinds of sensitivities supplied fromthe color interpolation section 162 based on the original positioninformation of the sensitivity Si supplied from the extraction section161 to produce a sensitivity mosaic image MsG, and supplies thesensitivity mosaic image MsG to the sensitivity uniformization section153. The insertion section 165 combines a number of images Bsi of a Bcomponent equal to the number of kinds of sensitivities supplied fromthe color interpolation section 162 based on the original positioninformation of the sensitivity Si supplied from the extraction section161 to produce a sensitivity mosaic image MsB, and supplies thesensitivity mosaic image MsB to the sensitivity uniformization section154.

[0390]FIG. 75 shows an example of a configuration of the sensitivityuniformization section 152. In the sensitivity uniformization section152, the sensitivity mosaic image MsR supplied from the insertionsection 163 of the by-sensitivity-basis color interpolation section 151is supplied to a local sum calculation section 171. The local sumcalculation section 171 performs, for each pixel of the sensitivitymosaic image MsR, a local sum calculation process using pixelsneighboring with the pixel and supplies resulting the local sumcorresponding to each of the pixels to a synthetic sensitivitycompensation section 172. The synthetic sensitivity compensation section172 collates the local sums with a synthetic sensitivity compensationLUT 173 to acquire corresponding compensation values and produces anoutput image R using the compensation values as pixel values. Thesynthetic sensitivity compensation LUT 173 can supply a correspondingcompensation value when a local sum is inputted as an index thereto.

[0391] It is to be noted that examples of configurations of thesensitivity uniformization sections 153 and 154 are similar to theexample of the configuration of the sensitivity uniformization section152 shown in FIG. 75, and therefore, description of them is omitted.

[0392] Subsequently, a third demosaic process by the third example ofthe configuration of the image processing section 7 shown in FIG. 73 isdescribed with reference to a flow chart of FIG. 76.

[0393] At step 181, the by-sensitivity-basis color interpolation section151 performs a by-sensitivity-basis color interpolation process for thecolor and sensitivity mosaic image to produce an R component sensitivitymosaic image MsR, a G component sensitivity mosaic image MsG and a Bcomponent sensitivity mosaic image MsB and supplies them to thesensitivity uniformization sections 152 to 154, respectively.

[0394] Details of the by-sensitivity-basis color interpolation processof the by-sensitivity-basis color interpolation section 151 aredescribed with reference to a flow chart of FIG. 77. At step S191, theextraction section 161 discriminates whether or not all sensitivities(in the present case, S0 and S1) included in the sensitivity mosaicpattern information have been designated. If the extraction section 161discriminates that all sensitivities have not been designated, then theprocessing advances to step S192.

[0395] At step S192, the extraction section 161 determines one of allkinds of sensitivities included in the sensitivity mosaic patterninformation. The designated sensitivity is represented by Si.

[0396] At step S193, the extraction section 161 extracts only pixels ofthe sensitivity Si from among all pixels of the color and sensitivitymosaic image to produce a color mosaic image McSi of the sensitivity Siand supplies the color mosaic image McSi to the color interpolationsection 162. Further, the extraction section 161 produces originalposition information of the sensitivity Si which keeps a positionalrelationship between the color mosaic image McSi and the original colorand sensitivity mosaic image and supplies the original positioninformation to the insertion sections 163 to 165. Further, theextraction section 161 produces color mosaic pattern information of thesensitivity Si representative of a color mosaic arrangement of the colormosaic image McSi and supplies the color mosaic pattern information tothe color interpolation section 162.

[0397] Details of the process at step S193 are described with referenceto FIGS. 78 and 79.

[0398] Since pixels of the sensitivity Si extracted do not have a pixeldistance of the original color and sensitivity mosaic image, the colormosaic image McSi of the sensitivity Si produced is formed in a latticewherein the pixel distance, the original and the direction are differentfrom those of the original color and sensitivity mosaic image.Therefore, the extraction section 61 produces, simultaneously withproduction of the color mosaic image McSi, original position informationwhich allows, for each pixel, information of the original position to bereferred to based on a corresponding relationship between the coordinatesystem of the original color and sensitivity mosaic image and thecoordinate system of the color mosaic image McSi.

[0399] The corresponding relationship between the coordinate systems ofthe original color and sensitivity mosaic image and the color mosaicimage McSi to be produced is such as illustrated in FIG. 78 or 79.Referring to FIGS. 78 and 79, the original color and sensitivity mosaicimage is indicated on the xy coordinate system while the color mosaicimage McSi is indicated on the st coordinate system. Further, of thecolor and sensitivity mosaic image represents a pixel of the sensitivityS0, and of the color and sensitivity mosaic image represents a pixel ofthe sensitivity S0 By using the st coordinate system set obliquely withrespect to the xy coordinate system in this manner, pixels of thesensitivity Si disposed in a checkered manner on the original color andsensitivity mosaic image can be extracted as a pixel arrangement of anequal distance lattice.

[0400] Extraction of pixels of the sensitivity S0 represented by of thecolor and sensitivity mosaic image is described with reference to FIG.78. For example, a pixel A in FIG. 78 is represented as (x_(A), y_(A))on the xy coordinate system which represents the original color andsensitivity mosaic image but is represented as (s_(A), t_(A)) on the stcoordinate system which represents the color mosaic image McSi to beproduced. (s_(A), t_(A)) and (x_(A), y_(A)) have such relationships asrepresented by the following expression (22):

s _(A)={(x _(A)−1)+y _(A)}/2

t _(A)={(x _(max)−1−x _(A))+y _(A)}/2  (22)

[0401] The extraction section 161 applies the coordinates (x_(A), y_(A))of the pixel of the sensitivity S0 of the original color and sensitivitymosaic image to the expression (22) to calculate the coordinates (s_(A),t_(A)) on the color mosaic image McSi and uses the value of the pixelfor the coordinates to produce a color mosaic image McSi.Simultaneously, the extraction section 161 places the coordinates(x_(A), y_(A)) in a corresponding relationship to the coordinates(s_(A), t_(A)) into the original position information of the sensitivityS0.

[0402] Extraction of a pixel of the sensitivity S1 represented by of thecolor and sensitivity mosaic image is described with reference to FIG.79. For example, a pixel B in FIG. 79 is represented as (x_(B), y_(B))on the xy coordinate system which represents the original color andsensitivity mosaic image but is represented as (s_(B), t_(B)) on the stcoordinate system which represents the color mosaic image McSi to beproduced. (s_(B), t_(B)) and (x_(B), y_(B)) have such a relationship asrepresented by the following expression (23):

s _(B)=(x _(B) +y _(B))/2

t _(B)={(x _(max)−1−x _(B))+y _(B)}/2  (23)

[0403] The extraction section 161 applies the coordinates (x_(B), y_(B))of the pixel of the sensitivity S1 of the original color and sensitivitymosaic image to the expression (22) to calculate the coordinates (s_(B),t_(B)) on the color mosaic image McSi and uses the value of the pixelfor the coordinates to produce a color mosaic image McSi.Simultaneously, the extraction section 161 places the coordinates(x_(B), y_(B)) in a corresponding relationship to the coordinates(s_(B), t_(B)) into the original position information of the sensitivityS1.

[0404] Referring back to FIG. 77, the color interpolation section 162interpolates RGB components of all pixels of the color mosaic image McSifrom the extraction section 161 to produce images Rsi, Gsi and Bsi andsupplies the images Rsi, Gsi and Bsi to the corresponding insertionsections 163 to 165, respectively. It is to be noted that details ofprocessing of the color interpolation section 162 are similar to thoseof the color interpolation process of the color interpolation section 52described with reference to FIG. 55, and therefore, description of themis omitted.

[0405] The processing returns to step S191 so that the processing atsteps S191 to S194 is repeated until it is discriminated at step S191that all sensitivities included in the sensitivity mosaic patterninformation have been designated. When it is discriminated at step S191that all sensitivities included in the sensitivity mosaic patterninformation have been designated, the processing advances to step S195.

[0406] At step S195, the insertion section 163 combines a number ofimages Rsi of an R component (in the present case, the images Rs0 andimages Rs1) equal to the number of kinds of sensitivities supplied fromthe color interpolation section 162 based on all of the originalposition information supplied from the extraction section 161 to producea sensitivity mosaic image MsR, and supplies the sensitivity mosaicimage MsR to the sensitivity uniformization section 152. Similarly, theinsertion section 164 produces and supplies a sensitivity mosaic imageMsG to the sensitivity uniformization section 153, and the insertionsection 165 produces and supplies a sensitivity mosaic image MsB to thesensitivity uniformization section 154.

[0407] The processing returns to step S182 of FIG. 76. At step S182, thesensitivity uniformization section 152 performs a sensitivityuniformization process for the R component sensitivity mosaic image MsRto produce an output image R. The sensitivity uniformization section 153performs a sensitivity uniformization process for the G componentsensitivity mosaic image MsG to produce an output image G. Thesensitivity uniformization section 154 performs a sensitivityuniformization for the B component sensitivity mosaic image MsB toproduce an output image B.

[0408] The sensitivity uniformization process of the sensitivityuniformization section 152 is described with reference to a flow chartof FIG. 80. At step S201, the local sum calculation section 171discriminates whether or not all pixels of the R component sensitivitymosaic image MsR have been used as a noticed pixel. If the local sumcalculation section 171 discriminates that all pixels have not been usedas a noticed pixel, then the processing advances to step S202. At stepS202, the local sum calculation section 171 determines one by one pixelas a noticed pixel beginning with the left lowermost pixel and endingwith the right uppermost pixel of the sensitivity mosaic image MsR.

[0409] At step S203, the local sum calculation section 171 calculates alocal sum corresponding to the noticed pixel and supplies it to thesynthetic sensitivity compensation section 172. More particularly, thepixel values of 5×5 pixels (hereinafter referred to as reference pixels)centered at the noticed pixel are extracted, and the pixel values aremultiplied by such filter coefficients set in advance corresponding torelative positions of the reference pixels to the noticed pixel as seenin FIG. 81, whereafter the sum total of the products is arithmeticallyoperated. Further, the sum total of the products is divided by the sumtotal of the 25 filter coefficients, and the quotient is determined as alocal sum corresponding to the noticed pixel.

[0410] At step S204, the synthetic sensitivity compensation section 172collates the local sum with the synthetic sensitivity compensation LUT173 to acquire a corresponding compensation value and determines thecompensation value as a pixel value of the output image R correspondingto the noticed pixels.

[0411] The processing returns to step S201 so that the processing atsteps S201 to S204 is repeated until it is discriminated at step S201that all pixels have been used as a noticed pixel. When it isdiscriminated at step S201 that all pixels have been used as a noticedpixel, the sensitivity uniformization process is ended, and theprocessing returns to FIG. 76.

[0412] It is to be noted that, although also the sensitivityuniformization sections 153 and 154 execute a similar sensitivityuniformization process in parallel to the sensitivity uniformizationprocess of the sensitivity uniformization section 152, detaileddescription of it is omitted.

[0413] Description of the third demosaic process by the third example ofthe configuration of the image processing section 7 is ended therewith.

[0414] Subsequently, an outline of a fourth demosaic process of theimage processing system including the image processing section 7 as aprincipal component is described.

[0415] The fourth demosaic process includes a luminance image productionprocess for producing a luminance image from a color and sensitivitymosaic image obtained by processing of the image pickup system, and amonochromatic image process for producing output images R, G and B usingthe color and sensitivity mosaic image and the luminance image.

[0416]FIG. 82 shows a fourth example of a configuration of the imageprocessing section 7 which principally executes the fourth demosaicprocess.

[0417] In the fourth example of the configuration of the imageprocessing section 7, a color and sensitivity mosaic image from theimage pickup system, color mosaic pattern information which indicates acolor mosaic arrangement of the color and sensitivity mosaic image andsensitivity mosaic pattern information which indicates a sensitivitymosaic arrangement of the color and sensitivity mosaic image aresupplied to a luminance image production section 181 and monochromaticimage production sections 182 to 184.

[0418] It is to be noted that, in the following description, unlessotherwise specified, the color and sensitivity mosaic image has thecolor and sensitivity mosaic pattern P2 of FIG. 6. In particular, eachpixel has a color which is one of the three primary colors of R, G and Band has a sensitivity of one of S0 and S1, and further, where attentionis paid only to the color irrespective of the sensitivity, the pixels ofthe color are arranged in a Bayer arrangement.

[0419] However, the configuration and the operation described below canbe applied also to another color and sensitivity mosaic image whichincludes three colors other than R, G and B or a further color andsensitivity mosaic image which includes four colors.

[0420] The luminance image production section 181 performs a luminanceimage production process for the color and sensitivity mosaic imagesupplied thereto and supplies a resulting luminance image to themonochromatic image production sections 182 to 184.

[0421] The monochromatic image production section 182 produces an outputimage R using the color and sensitivity mosaic image and the luminanceimage supplied thereto. The monochromatic image production section 183produces an output image G using the color and sensitivity mosaic imageand the luminance image supplied thereto. The monochromatic imageproduction section 184 produces an output image B using the color andsensitivity mosaic image and luminance image supplied thereto.

[0422]FIG. 83 shows a first example of a configuration of the luminanceimage production section 181. In the first example of the configurationof the luminance image production section 181, a color and sensitivitymosaic image, color mosaic pattern information and sensitivity mosaicpattern information are supplied to estimation sections 191 to 193.

[0423] The estimation section 191 performs an R component estimationprocess for the color and sensitivity mosaic image and supplies anestimation value R′ of an R component for each pixel obtained by theprocess to a multiplier 194. The estimation section 192 performs a Gcomponent estimation process for the color and sensitivity mosaic imageand supplies an estimation value G′ of a G component for each pixelobtained by the process to another multiplier 195. The estimationsection 193 performs a B component estimation process for the color andsensitivity mosaic image and supplies an estimation value B′ of a Bcomponent for each pixel obtained by the process to a further multiplier196.

[0424] The multiplier 194 multiplies the estimation value R′ suppliedfrom the estimation section 191 by a color balance coefficient KR andoutputs the product to an adder 197. The multiplier 195 multiplies theestimation value G′ supplied from the estimation section 192 by a colorbalance coefficient KG and outputs the product to the adder 197. Themultiplier 196 multiplies the estimation value B′ supplied from theestimation section 193 by a color balance coefficient K_(B) and outputsthe product to the adder 197.

[0425] The adder 197 adds the product R′·k_(R) inputted from themultiplier 194, the product G′·k_(G) inputted from the multiplier 195and the product B′·k_(B) inputted from the multiplier 196, and producesa luminance candidate image wherein the resulting sum is used as a pixelvalue and supplies the luminance candidate image to a noise removalsection 198.

[0426] Here, the color balance coefficients k_(R), k_(G) and k_(B) arevalues set in advance and, for example, k_(R)=0.3, k_(G)=0.6 andk_(B)=0.1. It is to be noted that, basically, the color balancecoefficients k_(R), k_(G) and k_(B) may have any values only if they canbe used to calculate, as a luminance candidate value, a value having acorrelation to a luminance variation. Accordingly, for example, thecolor balance coefficients may be k_(R)=k_(G)=k_(B).

[0427] The noise removal section 198 performs a noise removal processfor the luminance candidate image supplied from the adder 197 andsupplies the resulting luminance image to monochromatic image productionsections 182 to 184.

[0428]FIG. 84 shows an example of a configuration of the monochromaticimage production section 182. In the monochromatic image productionsection 182, the color and sensitivity mosaic image, the color mosaicpattern information and the sensitivity mosaic pattern information aresupplied to an interpolation section 201. The luminance image issupplied to a ratio value calculation section 202 and a multiplier 203.

[0429] The interpolation section 201 performs an interpolation processfor the color and sensitivity mosaic image and outputs an R candidateimage wherein all resulting pixels have pixel values of an R componentto the ratio value calculation section 202. The ratio value calculationsection 202 calculates a low-frequency component of an intensity ratio(the low-frequency component is hereinafter referred to merely as anintensity ratio) between corresponding pixels of the R candidate imageand the luminance image and produces ratio value information whichrepresents an intensity ratio corresponding to each pixel, and suppliesthe ratio value information to the multiplier 203.

[0430] The multiplier 203 multiplies the pixel value of each pixel ofthe luminance image by the corresponding intensity ratio and produces anoutput image R having the product as a pixel value.

[0431] It is to be noted that, since also examples of a configuration ofthe monochromatic image production sections 183 and 184 are similar tothe example of the configuration of the monochromatic image productionsection 182, description of them is omitted.

[0432] Now, the fourth demosaic process by the fourth example of theconfiguration of the image processing section 7 is described withreference to a flow chart of FIG. 85.

[0433] At step S211, the luminance image production section 181 performsa luminance image production process for the color and sensitivitymosaic image to produce a luminance image and supplies the luminanceimage to the monochromatic image production sections 182 to 184.

[0434] The luminance image production process of the luminance imageproduction section 181 is described with reference to a flow chart ofFIG. 86.

[0435] At step S221, the estimation sections 191 to 193 discriminatewhether or not all pixels of the color and sensitivity mosaic image havebeen used as a noticed pixel. If the estimation sections 191 to 193discriminate that all pixels have not been used as a noticed pixel, thenthe processing advances to step S222. At step S222, the estimationsections 191 to 193 determine one by one pixel as a noticed pixelbeginning with the left lowermost pixel and ending with the rightuppermost pixel of the color and sensitivity mosaic image.

[0436] At step S223, the estimation section 191 performs an R componentestimation process for the color and sensitivity mosaic image toestimate an estimation value R′ corresponding to the noticed pixel andsupplies the estimation value R′ to the multiplier 194. The estimationsection 192 performs a G component estimation process for the color andsensitivity mosaic image to estimate an estimation value G′corresponding to the noticed pixel and supplies the estimation value G′to the multiplier 194. The estimation section 193 performs a B componentestimation process for the color and sensitivity mosaic image toestimate an estimation value B′ corresponding to the noticed pixel andsupplies the estimation value B′ to the multiplier 194.

[0437] The R component estimation process of the estimation section 191is described with reference to a flow chart of FIG. 87. At step S231,the estimation section 191 refers to the color mosaic patterninformation and the sensitivity mosaic pattern information to detectthose of pixels neighboring with the noticed pixel (for example, 15×15pixels centered at the noticed pixel) which have an R component and havethe sensitivity S0, and extracts the pixel values of the detected pixels(hereinafter referred to as reference pixels).

[0438] At step S232, the estimation section 191 acquires a number ofsuch R component interpolation filter coefficients set in advancecorresponding to relative positions of the reference pixels to thenoticed pixel as shown in FIG. 88, the number being equal to the numberof the reference pixels. Further, the estimation section 191 multipliesthe pixel values of the reference pixels and the corresponding filtercoefficients and arithmetically operates the sum total of the products.Furthermore, the estimation section 191 divides the sum total of theproducts by the sum total of the used R component interpolation filtercoefficients to acquire a first quotient.

[0439] At step S233, the estimation section 191 refers to the colormosaic pattern information and the sensitivity mosaic patterninformation to detect those of pixels neighboring with the noticed pixel(for example, 15×15 pixels centered at the noticed pixel) which have anR component and have the sensitivity S1, and extracts the pixel valuesof the detected pixels (hereinafter referred to as reference pixels).

[0440] At step S234, the estimation section 191 acquires a number of Rcomponent interpolation filter coefficients corresponding to relativepositions of the reference pixels to the noticed pixel, the number beingequal to the number of the reference pixels. Further, the estimationsection 191 multiplies the pixel values of the reference pixels and thecorresponding filter coefficients and arithmetically operates the sumtotal of the products. Furthermore, the estimation section 191 dividesthe sum total of the products by the sum total of the used interpolationfilter coefficients to acquire a second quotient.

[0441] At step S235, the estimation section 191 adds the first quotientacquired at step S232 and the second quotient acquired at step S234. Atstep S235, the estimation section 191 collates the sum of the firstquotient and the second quotient arithmetically operated at step S235with a synthetic sensitivity compensation LUT (hereinafter described)built therein to acquire a compensation value of a compensatedsensitivity characteristic. The acquired compensation value isdetermined as an estimation value R′ corresponding to the noticed pixel.The processing returns to step S224 of FIG. 86.

[0442] It is to be noted that, since the G component interpolationprocesses of the estimation section 192 and the B componentinterpolation processes of the estimation section 193 are similar to theR component interpolation process of the estimation section 191,description of them is omitted. It is to be noted, however, in the Gcomponent estimation process of the estimation section 192, referencepixels are detected from among 7×7 pixels centered at the noticed pixel,and further, the G component interpolation filter coefficientsillustrated in FIG. 89 are used.

[0443] Here, the synthetic sensitivity compensation LUT used by theestimation section 191 is described with reference to FIGS. 90 to 92.FIG. 90 shows a characteristic curve b of pixels of the sensitivity S0and another characteristic curve a of pixels of the sensitivity S1, andthe axis of abscissa indicates the intensity of incoming light and theaxis of ordinate indicate the pixel value. In FIG. 90, the sensitivityS1 of the high sensitivity has a sensitivity as high as four times thatof the sensitivity S0 of the low sensitivity.

[0444] In the estimation process, a first quotient calculated from apixel of the sensitivity S0 measured with such a characteristic asindicated by the characteristic curve b of FIG. 90 and a second quotientcalculated using a pixel of the sensitivity S1 measured with such acharacteristic as indicated by the characteristic curve a of FIG. 90 areadded. Accordingly, the sum of the first quotient and the secondquotient has such a characteristic synthesized from the characteristicsof the sensitivity S0 and the sensitivity S1 as indicated by acharacteristic curve c of FIG. 91.

[0445] While the synthesized characteristic curve c exhibits acharacteristic of a wide dynamic range from a low luminance to a highluminance, since it has a shape of a polygonal line, an original linearcharacteristic is restored using a characteristic curve reverse to thesensitivity characteristic curve c. More particularly, the sum of thefirst product and the second product is applied to a reversecharacteristic curve d to the sensitivity characteristic curve c of FIG.91 as shown in FIG. 92 to compensate for the non-linearity.

[0446] In particular, the synthetic sensitivity compensation LUT isobtained by converting the reverse characteristic curve d of FIG. 92into a lookup table.

[0447] Description is given with reference back to FIG. 86. At stepS224, the multiplier 194 multiplies the estimation value R′ suppliedfrom the estimation section 191 by a color balance coefficient k_(R) andoutputs the product to the adder 197. The multiplier 195 multiplies theestimation value G′ supplied from the estimation section 192 by a colorbalance coefficient k_(G) and outputs the product to the adder 197. Themultiplier 196 multiplies the estimation value B′ supplied from theestimation section 193 by a color balance coefficient k_(B) and outputsthe product to the adder 197. The adder 197 adds the product R′·k_(R)inputted from the multiplier 194, the product G′·k_(G) inputted from themultiplier 195 and the product B′·k_(B) inputted from the multiplier196, and determines the sum as a pixel value (luminance candidate value)of a luminance candidate image corresponding to the noticed pixel.

[0448] The processing returns to step S221 so that the processing atsteps S221 to S224 is repeated until it is discriminated at step S221that all pixels have been used as a noticed pixel. When it isdiscriminated at step S221 that all pixels have been used as a noticedpixel, the processing advances to step S225. It is to be noted that theluminance candidate image produced by the processes at steps S221 to 224is supplied to the noise removal section 198.

[0449] At step S225, the noise removal section 198 performs a noiseremoval process for the luminance candidate image supplied thereto fromthe adder 197 to produce a luminance image and supplies the luminanceimage to the monochromatic image production sections 182 to 184.

[0450] The noise removal process of the noise removal section 198 isdescribed with reference to a flow chart of FIG. 93. At step S241, thenoise removal section 198 discriminates whether or not all pixels of theluminance candidate image have been used as a noticed pixel. If thenoise removal section 198 discriminates that all pixels have not beenused as a noticed pixel, then the processing advances to step S242. Atstep S242, the noise removal section 198 determines one by one pixel asa noticed pixel beginning with the left lowermost pixel and ending withthe right uppermost pixel of the luminance candidate image.

[0451] At step S243, the noise removal section 198 acquires the pixelvalues (luminance candidate values) of the pixels positioned upwardly,downwardly, leftwardly and rightwardly of the noticed pixel andsubstitutes the acquired luminance candidate values of the pixelspositioned upwardly, downwardly, leftwardly and rightwardly of thenoticed pixel into variables a3, a0, a1 and a2, respectively.

[0452] At step S244, the noise removal section 198 executes a directionselective smoothing process to acquire a smoothed value corresponding tothe noticed pixel.

[0453] The direction selective smoothing process of the noise removalsection 198 is described with reference to a flow chart of FIG. 94. Atstep S251, the noise removal section 198 applies the variables a3, a0,a1, a2 to the following expression (24) to calculate a luminancegradient vector g corresponding to the noticed pixel:

luminance gradient vector g=(a2−a1, a3−a0)  (24)

[0454] At step S25-2, the noise removal section 198 arithmeticallyoperates the magnitude (absolute value) ∥∇∥ of the luminance gradientvector g.

[0455] At step S253, the noise removal section 198 applies the variablesa0 to a3 to the following expressions (25) and (26) to calculate asmoothed component Hh in the horizontal direction and a smoothedcomponent Hv in the vertical direction corresponding to the noticedpixel:

Hh=(a1+a2)/2  (25)

Hv=(a3+a0)/2  (26)

[0456] At step S254, the noise removal section 198 arithmeticallyoperates a significance wh in the horizontal direction and asignificance wv in the vertical direction corresponding to the absolutevalue ∥g∥ of the luminance gradient vector g.

[0457] More particularly, where the absolute value ∥g∥ of the luminancegradient vector g is higher than 0, the absolute value of the innerproduct of the normalized luminance gradient vector g/∥g∥ and the vector(1, 0) is subtracted from 1 to obtain the significance wh in thehorizontal direction as given by the following expression (27). Further,the absolute value of the inner product of the normalized luminancegradient vector g/∥g∥ and the vector (0, 1) is subtracted from 1 toobtain the significance wv in the vertical direction as given by thefollowing expression (28).

wh=1−|(g/∥g∥, (1, 0))|  (27)

wv=1−|(g/∥g∥, (0, 1))|  (28)

[0458] Where the absolute value ∥g∥ of the luminance gradient vector gis 0, the smoothing contribution rate wh in the horizontal direction andthe smoothing contribution rate wv in the vertical direction are bothset to 0.5.

[0459] At step S255, the noise removal section 198 arithmeticallyoperates a smoothed value α corresponding to the noticed pixel using thefollowing expression (29):

α=(wh·Hh+wv−Hv)/(wh+wv)  (29)

[0460] The processing returns to step S245 of FIG. 93. At step S245, thenoise removal section 198 arithmetically operates an average valuebetween the pixel value (luminance candidate value) of the noticed pixeland the smoothed value α corresponding to the noticed pixel calculatedat step S244 and determines the average value as a pixel value(luminance value) of the luminance image corresponding to the noticedpixel.

[0461] The processing returns to step S241 so that the processing atsteps S241 to S245 is repeated until it is discriminated at step S241that all pixels have been used as a noticed pixel. When it isdiscriminated at step S241 that all pixels have been used as a noticedpixel, the noise removal process is ended and also the luminance imageproduction process is ended, and the processing returns to step S212 ofFIG. 85.

[0462] At step S212, the monochromatic image production sections 182 to184 produce the output images R, G, and B, respectively by using thesupplied color and sensitivity mosaic image and the luminance image.

[0463] A first monochromatic image production process of themonochromatic image production section 182 is described with referenceto a flow chart of FIG. 95.

[0464] At step S261, the interpolation section 201 performs aninterpolation process for the color and sensitivity mosaic image toproduce an R candidate image wherein all pixels have pixel values of anR component and outputs the R candidate image to the ratio valuecalculation section 202.

[0465] It is to be noted that the interpolation process of theinterpolation section 201 is similar to the R component estimationprocess of the estimation section 191 which composes the luminance imageproduction section 181 described hereinabove with reference to the flowchart of FIG. 87, and therefore, description of it is omitted.

[0466] At step S262, the ratio value calculation section 202 performs aratio value calculation process to calculate an intensity ratio andfurther produces ratio value information representative of the intensityratio corresponding to each pixel, and supplies the intensity ratio andthe ratio value information to the multiplier 203.

[0467] The ratio value calculation process of the ratio valuecalculation section 202 is described with reference to a flow chart ofFIG. 96. At step S271, the ratio value calculation section 202discriminates whether or not all pixels of the R candidate image havebeen used as a noticed pixel. If the ratio value calculation section 202discriminates that all pixels have not been used as a noticed pixel,then the processing advances to step S272. At step S272, the ratio valuecalculation section 202 determines one by one pixel as a noticed pixelbeginning with the left lowermost pixel and ending with the rightuppermost pixel of the R candidate image.

[0468] At step S273, the ratio value calculation section 202 refers tothose pixels which are positioned in the neighborhood of the noticedpixel (for example, 7×7 pixels centered at the noticed pixel) to acquirethe pixel values (monochromatic candidate values of R components) of thepixels. Further, the ratio value calculation section 202 extracts thepixel values (luminance values) of the pixels of the luminance imagewhich are positioned at the same coordinates as those of the referencepixels.

[0469] At step S274, the ratio value calculation section 202 acquires anumber of smoothing filter coefficients set in advance as shown in FIG.97 corresponding to relative positions of the reference pixels to thenoticed pixel, the number being equal to the number of the referencepixels.

[0470] At step S275, the ratio value calculation section 202 multipliesthe monochromatic candidate values for an R component of the referencepixels and the corresponding filter coefficients, divides the productsby the corresponding luminance values and arithmetically operates thesum total of the quotients. Further, the ratio value calculation section202 divides the sum total of the quotients by the sum total of the usedsmoothing filter coefficients and determines the quotient as anintensity ratio corresponding to the noticed pixel to produce ratiovalue information.

[0471] The processing returns to step S271 so that the processing atsteps S271 to S275 is repeated until it is discriminated at step S271that all pixels of the R candidate image have been used as a noticedpixel. When it is discriminated at step S271 that all pixels of the Rcandidate image have been used as a noticed pixel, the ratio valueinformation produced is supplied to the multiplier 203, and theprocessing returns to step S263 of FIG. 95.

[0472] At step S263, the multiplier 203 multiplies the pixel values ofthe pixels of the luminance image by the corresponding intensity ratiosto produce an output image R wherein the products are used as pixelvalues.

[0473] It is to be noted that, simultaneously with the firstmonochromatic image production process of the monochromatic imageproduction section 182, also the monochromatic image production sections183 and 184 execute similar processes.

[0474] Description of the fourth demosaic process by the fourth exampleof the configuration of the image processing section 7 is endedtherewith.

[0475]FIG. 98 shows a second example of a configuration of the luminanceimage production section 181. The second example of the configuration ofthe luminance image production section 181 replaces the estimationsections 191 to 193 of the first example of the configuration of theluminance image production section 181 shown in FIG. 83 with anestimation section 211.

[0476] In the second example of the configuration of the luminance imageproduction section 181, a color and sensitivity mosaic image, colormosaic pattern information and sensitivity mosaic pattern informationare supplied to the estimation section 211.

[0477] The estimation section 121 performs a component estimationprocess for the color and sensitivity mosaic image and supplies anestimation value R′ of an R component, a estimation value G′ of a Gcomponent and an estimation value B′ of a B component for each pixelobtained by the component estimation process to the correspondingmultipliers 194 to 196, respectively.

[0478] It is to be noted that the elements from the multiplier 194 tothe noise removal section 198 included in the second example of theconfiguration of the luminance image production section 181 are similarto the elements from the multiplier 194 to the noise removal section 198included in the first example of the configuration of the luminanceimage production section 181 shown in FIG. 83 in which like referencenumerals are applied, and therefore, description of them is omitted.

[0479] Now, the estimation process for RGB components by the estimationsection 211 is described with reference to a flow chart of FIG. 99. Itis to be noted that the estimation process for RGB components is aprocess which can be executed in place of the R component estimationprocess described hereinabove with reference to FIG. 87 as a process atstep S223 of FIG. 86. Accordingly, the processing at steps S281 et seqis described assuming that a noticed pixel of a color and sensitivitymosaic image has already been determined by the estimation section 211.

[0480] At step S281, the estimation section 211 calculates an estimatedpixel value C0 corresponding to the noticed pixel through an estimatedpixel value C0 interpolation process wherein the pixel values of suchfour pixels centered at the noticed pixel as shown in FIG. 100 are used.The estimated pixel value C0 interpolation process is described withreference to a flow chart of FIG. 101.

[0481] At step S291, the estimation section 211 substitutes the pixelvalues of the four pixels positioned upwardly, downwardly, leftwardlyand rightwardly of the noticed pixel indicated by ∘ each with a space ofone pixel left therebetween into variables a3, a0, a1 and a2 and appliesa direction selective smoothing process described hereinabove withreference to FIG. 94 to arithmetically operate a smoothed value α.

[0482] The process of substituting the pixel values of four pixelspositioned upwardly, downwardly, leftwardly and rightwardly of adesignated pixel into the variables a3, a0, a1 and a2 and applying thedirection selective smoothing process described hereinabove withreference to FIG. 94 to arithmetically operate a smoothed value α inthis manner is hereinafter defined as a vertical direction selectivesmoothing process corresponding to the designated pixel.

[0483] At step S292, the estimation section 211 adds the smoothed valueα obtained at step S291 to the pixel value of the noticed pixel anddetermines the sum as the estimated pixel value C0 of the noticed pixel.The processing returns to step S282 of FIG. 99.

[0484] At step S282, the estimation section 211 calculates an estimatedpixel value C1 corresponding to the noticed pixel through an estimatedpixel value C1 interpolation process wherein such 12 pixels centered atthe noticed pixel as shown in FIG. 102 are used. The estimated pixelvalue C1 interpolation process is described with reference to a flowchart of FIG. 103.

[0485] At step S301, the estimation section 211 discriminates whether ornot the color of the noticed pixel is G. If the estimation section 211discriminates that the color of the noticed pixel is G, then theprocessing advances to step S302. At step S302, the estimation section211 substitutes the pixel values of four pixels positioned leftwardlydownwards, leftwardly upwards, rightwardly downwards and rightwardlyupwards in the neighborhood of the noticed pixel represented by ∘ asshown in FIG. 102 into the variables a0, a1, a2 and a3, respectively,and applies the direction selective smoothing process describedhereinabove with reference to FIG. 94 to arithmetically operate asmoothed value α.

[0486] The process of substituting the pixel values of four pixelspositioned leftwardly downwards, leftwardly upwards, rightwardlydownwards and rightwardly upwards in the neighborhood of a designatedpixel into the variables a0, a1, a2 and a3, respectively, and applyingthe direction selective smoothing process described hereinabove withreference to FIG. 94 to arithmetically operate a smoothed value α ishereinafter defined as an oblique direction selective smoothing processcorresponding to the designated pixel.

[0487] At step S303, the estimation section 211 multiplies the smoothedvalue α obtained at step S302 by 2 and determines the product as anestimated pixel value C1 of the noticed pixel. The processing returns tostep S283 of FIG. 99.

[0488] It is to be noted that, if it is discriminated at step S301 thatthe color of the noticed pixel is not G, then the processing advances tostep S304.

[0489] At step S304, the estimation section 211 executes the verticaldirection selective smoothing process using four pixels positioned witha space of one pixel left from the pixel neighboring leftwardly upwardsof the noticed pixel to calculate a smoothed value α and substitutes thesmoothed value α into the variable al. At step S305, the estimationsection 211 executes the vertical direction selective smoothing processusing four pixels positioned with a space of one pixel left from thepixel neighboring rightwardly downwards of the noticed pixel tocalculate a smoothed value α and substitutes the smoothed value α intothe variable a2. At step S306, the estimation section 211 substitutesthe pixel value of the pixel neighboring leftwardly downwards of thenoticed pixel into the variable a0 and substitutes the pixel value ofthe pixel neighboring rightwardly upwards of the noticed pixel into thevariable a3.

[0490] At step S307, the estimation section 211 applies the variablesa0, a1, a2 and a3 whose values have been set at steps S304 to S306 tothe direction selective smoothing process described hereinabove withreference to FIG. 94 to arithmetically operate a smoothed value α anddetermines the value of the smoothed value α as a smoothed value α′.

[0491] At step S308, the estimation section 211 executes the verticaldirection selective smoothing process using four pixels positioned witha space of one pixel left from the pixel neighboring leftwardlydownwards of the noticed pixel to calculate a smoothed value α andsubstitutes the smoothed value α into the variable a0. At step S309, theestimation section 211 executes the vertical direction selectivesmoothing process using four pixels positioned with a space of one pixelleft from the pixel neighboring rightwardly upwards of the noticed pixelto calculate a smoothed value α and substitutes the smoothed value αinto the variable a3. At step S310, the estimation section 211substitutes the pixel value of the pixel neighboring leftwardly upwardsof the noticed pixel into the variable al and substitutes the pixelvalue of the pixel neighboring rightwardly downwards of the noticedpixel into the variable a2.

[0492] At step S311, the estimation section 211 applies the variablesa0, a1, a2 and a3 whose values have been set at steps S308 to S310 tothe direction selective smoothing process described hereinabove withreference to FIG. 94 to arithmetically operate a smoothed value α anddetermines the value of the smoothed value α as a smoothed value α″.

[0493] At step S312, the estimation section 211 adds the smoothed valueα′ obtained at step S307 and the smoothed value α″ obtained at step S311and determines the sum as an estimated pixel value C1 corresponding tothe noticed pixel. The processing returns to step S283 of FIG. 99.

[0494] At step S283, the estimation section 211 calculates a estimatedpixel value C2 corresponding to the noticed pixel through a estimatedpixel value C2 interpolation process wherein such four pixels centeredat the noticed pixel as shown in FIG. 104A or such eight pixels centeredat the noticed pixel as shown in FIG. 104B are used. The estimated pixelvalue C2 interpolation process is described with reference to a flowchart of FIG. 105.

[0495] At step S321, the estimation section 211 discriminates whether ornot the color of the noticed pixel is G. If the estimation section 211discriminates that the color of the noticed pixel is G, then theprocessing advances to step S322.

[0496] At step S322, the estimation section 211 executes the verticaldirection selective smoothing process using four pixels positioned witha space of one pixel left from the pixel neighboring upwardly of thenoticed pixel to calculate a smoothed value α and determines it as asmoothed value α′.

[0497] At step S323, the estimation section 211 executes the verticaldirection selective smoothing process using four pixels positioned witha space of one pixel left from the pixel neighboring downwardly of thenoticed pixel to calculate a smoothed value α and determines it as asmoothed value α″.

[0498] At step S324, the estimation section 211 adds an average value ofthe pixel value of the pixel neighboring downwardly of the noticed pixeland the smoothed value α′ obtained at step S322 and an average value ofthe pixel value of the pixel neighboring upwardly of the noticed pixeland the smoothed value α″ obtained at step S323 and determines the sumas an estimated pixel value C2 corresponding to the noticed pixel. Theprocessing returns to step S284 of FIG. 99.

[0499] It is to be noted that, if it is discriminated at step S321 thatthe color of the noticed pixel is not G, then the processing advances tostep S325.

[0500] At step S325, the estimation section 211 executes the obliquedirection selective smoothing process using four pixels positionedobliquely in the neighborhood of the pixel neighboring leftwardly of thenoticed pixel to calculate a smoothed value α and substitutes it intothe variable al. At step S326, the estimation section 211 executes theoblique direction selective smoothing process using four pixelspositioned obliquely in the neighborhood of the pixel neighboringrightwardly of the noticed pixel to calculate a smoothed value α andsubstitutes it into the variable a2. At step S327, the estimationsection 211 substitutes the pixel value of the pixel neighboringdownwardly of the noticed pixel into the variable a0 and substitutes thepixel value of the pixel neighboring upwardly of the noticed pixel intothe variable a3.

[0501] At step S328, the estimation section 211 applies the variablesa0, a1, a2 and a3 whose values have been set at steps S325 to S327 tothe direction selective smoothing process described hereinabove withreference to FIG. 94 to arithmetically operate a smoothed value α anddetermines the value of the smoothed value α as a smoothed value α′.

[0502] At step S329, the estimation section 211 executes the obliquedirection selective smoothing process using four pixels positionedobliquely in the neighborhood of the pixel neighboring downwardly of thenoticed pixel to calculate a smoothed value α and substitutes it intothe variable a0. At step S330, the estimation section 211 executes theoblique direction selective smoothing process using four pixelspositioned obliquely in the neighborhood of the pixel neighboringupwardly of the noticed pixel to calculate a smoothed value α andsubstitutes it into the variable a3. At step S331, the estimationsection 211 substitutes the pixel value of the pixel neighboringleftwardly of the noticed pixel into the variable al and substitutes thepixel value of the pixel neighboring rightwardly of the noticed pixelinto the variable a2.

[0503] At step S332, the estimation section 211 applies the variablesa0, a1, a2 and a3 whose values have been set at steps S329 to S331 tothe direction selective smoothing process described hereinabove withreference to FIG. 94 to arithmetically operate a smoothed value α anddetermines the value of the smoothed value α as a smoothed value α″.

[0504] At step S333, the estimation section 211 adds the smoothed valueα′ obtained at step S328 and the smoothed value α″ obtained at step S322and determines the sum as an estimated pixel value C2 corresponding tothe noticed pixel. The processing returns to step S284 of FIG. 99.

[0505] At step S284, the estimation section 211 calculates a estimatedpixel value C3 corresponding to the noticed pixel through an estimatedpixel value C3 interpolation process wherein such eight pixels centeredat the noticed pixel as shown in FIG. 106 are used. The estimated pixelvalue C3 interpolation process is described with reference to a flowchart of FIG. 107.

[0506] At step S341, the estimation section 211 discriminates whether ornot the color of the noticed pixel is G. If the estimation section 211discriminates that the color of the noticed pixel is G, then theprocessing advances to step S342.

[0507] At step S342, the estimation section 211 executes the verticaldirection selective smoothing process using four pixels positioned witha space of one pixel left from the pixel neighboring rightwardly of thenoticed pixel to calculate a smoothed value α and determines it as asmoothed value α′.

[0508] At step S343, the estimation section 211 executes the verticaldirection selective smoothing process using four pixels positioned witha space of one pixel left from the pixel neighboring leftwardly of thenoticed pixel to calculate a smoothed value α and determines it as asmoothed value α″.

[0509] At step S344, the estimation section 211 adds an average value ofthe pixel value of the pixel neighboring leftwardly of the noticed pixeland the smoothed value α′ obtained at step S342 and an average value ofthe pixel value of the pixel neighboring rightwardly of the noticedpixel and the smoothed value α″ obtained at step S343 and determines thesum as an estimated pixel value C3 corresponding to the noticed pixel.The processing returns to step S285 of FIG. 99.

[0510] It is to be noted that, if it is discriminated at step S341 thatthe color of the noticed pixel is G, then the processing advances tostep S345. At step S345, the estimation section 211 sets the estimatedpixel value C3 corresponding to the noticed pixel to 0. The processingreturns to step S285 of FIG. 99.

[0511] At step S285, the estimation section 211 refers to the colormosaic pattern information and the sensitivity mosaic patterninformation to discriminate the color and the sensitivity of the noticedpixel, and applies, based on a result of the discrimination, theestimated pixel values C0 to C3 corresponding to the noticed pixelobtained at steps S281 to S284 to a synthetic sensitivity compensationLUT (similar to the synthetic sensitivity compensation LUT describedhereinabove with reference to FIGS. 90 to 92) built therein to calculateestimated values R′, G′ and B′.

[0512] In particular, where the color of the noticed pixel is G and thesensitivity is S0, a value LUT(C2) when the estimated pixel value C2 isapplied to the synthetic sensitivity compensation LUT is determined asthe estimated value R′, and a value LUT((C0+C1/)2)) when an averagevalue of the estimated pixel values C0+C1 is applied to the syntheticsensitivity compensation LUT is determined as the estimated value G′while a value LUT(C3) when the estimated pixel value C3 is applied tothe synthetic sensitivity compensation LUT is determined as theestimated value B′.

[0513] Where the color of the noticed pixel is G and the sensitivity isS1, a value LUT(C3) when the estimated pixel value C3 is applied to thesynthetic sensitivity compensation LUT is determined as the estimatedvalue R′, and a value LUT((C0+C1/)2)) when an average value of theestimated pixel values C0+C1 is applied to the synthetic sensitivitycompensation LUT is determined as the estimated value G′ while a valueLUT(C2) when the estimated pixel value C2 is applied to the syntheticsensitivity compensation LUT is determined as the estimated value B′.

[0514] Where the color of the noticed pixel is R, a value LUT (C0) whenthe estimated pixel value C0 is applied to the synthetic sensitivitycompensation LUT is determined as the estimated value R′, and a valueLUT(C2) when an average value of the estimated pixel value C2 is appliedto the synthetic sensitivity compensation LUT is determined as theestimated value G′ while a value LUT(C1) when the estimated pixel valueC1 is applied to the synthetic sensitivity compensation LUT isdetermined as the estimated value B′.

[0515] Where the color of the noticed pixel is B, a value LUT(C1) whenthe estimated pixel value C1 is applied to the synthetic sensitivitycompensation LUT is determined as the estimated value R′, and a valueLUT(C2) when an average value of the estimated pixel value C2 is appliedto the synthetic sensitivity compensation LUT is determined as theestimated value G′ while a value LUT(C0) when the estimated pixel valueC0 is applied to the synthetic sensitivity compensation LUT isdetermined as the estimated value B′.

[0516] Since, in the estimation process of RGB components by theestimation section 211, the estimated pixel values C0 to C3 producedmaking use of the direction selective smoothing process are used in sucha manner as described above, deterioration of the resolution of an imagesignal is suppressed.

[0517] Description of the estimation process for RGB components by theestimation section 211 is ended therewith.

[0518] Incidentally, it is described in the foregoing description thatthe monochromatic image production sections 183 and 184 of the fourthexample of the configuration of the image processing section 7 areconfigured similarly to the example of the configuration of themonochromatic image production section 182 shown in FIG. 84 and executea process similar to the monochromatic image production process (FIG.95) of the monochromatic image production section 182 described withreference to FIG. 95. However, the monochromatic image productionsections 182 to 184 may otherwise execute unique processes individuallyoptimized therefor in place of the monochromatic candidate image process(step S261 of FIG. 95) included in the monochromatic image productionprocess.

[0519] The R candidate image production process executed by themonochromatic image production section 182 in place of the monochromaticcandidate image production process at step S261 is described withreference to a flow chart of FIG. 108. It is to be noted that, for theconvenience of description, the interpolation section 201 which composesthe monochromatic image production section 182 is hereinafter referredto as interpolation section 201-R.

[0520] At step S351, the interpolation section 201-R discriminateswhether or not all pixels of the color and sensitivity mosaic image havebeen used as a noticed pixel for the first time. If the interpolationsection 201-R discriminates that all pixels have not been used as anoticed pixel for the first time, then the processing advances to stepS352. At step S352, the interpolation section 201-R determines one byone pixel as a noticed pixel for the first time beginning with the leftlowermost pixel and ending with the right uppermost pixel of the colorand sensitivity mosaic image.

[0521] At step S353, the interpolation section 201-R discriminateswhether or not the color of the noticed pixel for the first time is R.If the interpolation section 201-R discriminates that the color of thenoticed pixel for the first time is R, then the processing advances tostep S354. At step S354, the interpolation section 201-R executes thevertical direction selective smoothing process using four pixelspositioned upwardly, downwardly, leftwardly and rightwardly of thenoticed pixel for the first time with a space of one pixel lefttherebetween to calculate a smoothed value α. At step S355, theinterpolation section 201-R applies the sum of the pixel value of thenoticed pixel for the first time and the smoothed value α calculated atstep S354 to a synthetic sensitivity compensation LUT (a syntheticsensitivity compensation LUT similar to that described with reference toFIGS. 90 to 92) built therein and determines the resulting value as apixel value corresponding to the noticed pixel for the first time of anR candidate image. The processing returns to step S351.

[0522] It is to be noted that, if it is discriminated at step S353 thatthe color of the noticed pixel for the first time is not R, then theprocessing returns to step S351 skipping the steps S354 and S355.

[0523] Thereafter, the processing at steps S351 to S355 is repeateduntil it is discriminated at step S351 that all pixels of the color andsensitivity mosaic image have been used as a noticed pixel for the firsttime. When it is discriminated at step S351 that all pixels of the colorand sensitivity mosaic image have been used as a noticed pixel for thefirst time, the processing advances to step S356.

[0524] At step S356, the interpolation section 201-R discriminateswhether or not all pixels of the color and sensitivity mosaic image havebeen used as a noticed pixel for the second time. If the interpolationsection 201-R discriminates that all pixels have not been used as anoticed pixel for the second time, then the processing advances to stepS357. At step S357, the interpolation section 201-R determines one byone pixel as a noticed pixel for the second time beginning with the leftlowermost pixel and ending with the right uppermost pixel of the colorand sensitivity mosaic image.

[0525] At step S358, the interpolation section 201-R discriminateswhether or not the color of the noticed pixel for the second time is B.If the interpolation section 201-R discriminates that the color of thenoticed pixel for the second time is B, then the processing advances tostep S359. At step S359, the interpolation section 201-R executes theoblique direction selective smoothing process using four pixelspositioned obliquely in the neighborhood of the noticed pixel for thesecond time to calculate a smoothed value α. At step S360, theinterpolation section 201-R determines the smoothed value α calculatedat step S359 as a pixel value corresponding to the noticed pixel for thesecond time of the R candidate image. The processing returns to stepS356.

[0526] It is to be noted that, if it is discriminated at step S358 thatthe color of the noticed pixel for the second time is not B, then theprocessing returns to step S356 skipping the steps S359 and S360.

[0527] Thereafter, the processing at steps S356 to S360 is repeateduntil it is discriminated at step S356 that all pixels of the color andsensitivity mosaic image have been used as a noticed pixel for thesecond time. When it is discriminated at step S356 that all pixels ofthe color and sensitivity mosaic image have been used as a noticed pixelfor the second time, the processing advances to step S351.

[0528] At step S361, the interpolation section 201-R discriminateswhether or not all pixels of the color and sensitivity mosaic image havebeen used as a noticed pixel for the third time. If the interpolationsection 201-R discriminates that all pixels have not been used as anoticed pixel for the third time, then the processing advances to stepS362. At step S362, the interpolation section 201-R determines one byone pixel as a noticed pixel for the third time beginning with the leftlowermost pixel and ending with the right uppermost pixel of the colorand sensitivity mosaic image.

[0529] At step S363, the interpolation section 201-R discriminateswhether or not the color of the noticed pixel for the third time is G.If the interpolation section 201-R discriminates that the color of thenoticed pixel for the third time is G, then the processing advances tostep S364. At step S364, the interpolation section 201-R executes thevertical direction selective smoothing process using four pixelspositioned upwardly, downwardly, leftwardly and rightwardly of thenoticed pixel for the third time to calculate a smoothed value α. Atstep S365, the interpolation section 201-R determines the smoothed valueα calculated at step S364 as a pixel value corresponding to the noticedpixel for the third time of an R candidate image.

[0530] It is to be noted that, if it is discriminated at step S363 thatthe color of the noticed pixel for the third time is not G, then theprocessing returns to step S351 skipping the steps S364 and S365.

[0531] Thereafter, the processing at steps S361 to S365 is repeateduntil it is discriminated at step S361 that all pixels of the color andsensitivity mosaic image have been used as a noticed pixel for the thirdtime. When it is discriminated at step S361 that all pixels of the colorand sensitivity mosaic image have been used as a noticed pixel for thethird time, the R candidate image production process is ended.

[0532] The B candidate image production process executed by themonochromatic image production section 184 is described with referenceto a flow chart of FIG. 109. It is to be noted that, for the convenienceof description, the component of the monochromatic image productionsection 184 which corresponds to the interpolation section 201 of themonochromatic image production section 182 is hereinafter referred to asinterpolation section 201-B.

[0533] At step S371, the interpolation section 201-B discriminateswhether or not all pixels of the color and sensitivity mosaic image havebeen used as a noticed pixel for the first time. If the interpolationsection 201-B discriminates that all pixels have not been used as anoticed pixel for the first time, then the processing advances to stepS372. At step S372, the interpolation section 201-B determines one byone pixel as a noticed pixel for the first time beginning with the leftlowermost pixel and ending with the right uppermost pixel of the colorand sensitivity mosaic image.

[0534] At step S373, the interpolation section 201-B discriminateswhether or not the color of the noticed pixel for the first time is B.If the interpolation section 201-B discriminates that the color of thenoticed pixel for the first time is B, then the processing advances tostep S374. At step S374, the interpolation section 201-B executes thevertical direction selective smoothing process using four pixelspositioned upwardly, downwardly, leftwardly and rightwardly of thenoticed pixel for the first time with a space of one pixel lefttherebetween to calculate a smoothed value α. At step S375, theinterpolation section 201-B applies the sum of the pixel value of thenoticed pixel for the first time and the smoothed value α calculated atstep S374 to a synthetic sensitivity compensation LUT (a syntheticsensitivity compensation LUT similar to that described with reference toFIGS. 90 to 92) built therein and determines the resulting value as apixel value corresponding to the noticed pixel for the first time of a Bcandidate image. The processing returns to step S371.

[0535] It is to be noted that, if it is discriminated at step S373 thatthe color of the noticed pixel for the first time is not B, then theprocessing returns to step S371 skipping the steps S374 and S375.

[0536] Thereafter, the processing at steps S371 to S375 is repeateduntil it is discriminated at step S371 that all pixels of the color andsensitivity mosaic image have been used as a noticed pixel for the firsttime. When it is discriminated at step S371 that all pixels of the colorand sensitivity mosaic image have been used as a noticed pixel for thefirst time, the processing advances to step S376.

[0537] At step S376, the interpolation section 201-B discriminateswhether or not all pixels of the color and sensitivity mosaic image havebeen used as a noticed pixel for the second time. If the interpolationsection 201-B discriminates that all pixels have not been used as anoticed pixel for the second time, then the processing advances to stepS377. At step S377, the interpolation section 201-B determines one byone pixel as a noticed pixel for the second time beginning with the leftlowermost pixel and ending with the right uppermost pixel of the colorand sensitivity mosaic image.

[0538] At step S378, the interpolation section 201-B discriminateswhether or not the color of the noticed pixel for the second time is R.If the interpolation section 201-B discriminates that the color of thenoticed pixel for the second time is R, then the processing advances tostep S379. At step S379, the interpolation section 201-B executes theoblique direction selective smoothing process using four pixelspositioned obliquely in the neighborhood of the noticed pixel for thesecond time to calculate a smoothed value α. At step S380, theinterpolation section 201-B determines the smoothed value α calculatedat step S379 as a pixel value corresponding to the noticed pixel for thesecond time of the B candidate image. The processing returns to stepS376.

[0539] It is to be noted that, if it is discriminated at step S378 thatthe color of the noticed pixel for the second time is not R, then theprocessing returns to step S376 skipping the steps S379 and S380.

[0540] Thereafter, the processing at steps S376 to S380 is repeateduntil it is discriminated at step S376 that all pixels of the color andsensitivity mosaic image have been used as a noticed pixel for thesecond time. When it is discriminated at step S376 that all pixels ofthe color and sensitivity mosaic image have been used as a noticed pixelfor the second time, the processing advances to step S381.

[0541] At step S381, the interpolation section 201-B discriminateswhether or not all pixels of the color and sensitivity mosaic image havebeen used as a noticed pixel for the third time. If the interpolationsection 201-B discriminates that all pixels have not been used as anoticed pixel for the third time, then the processing advances to stepS382. At step S382, the interpolation section 201-B determines one byone pixel as a noticed pixel for the third time beginning with the leftlowermost pixel and ending with the right uppermost pixel of the colorand sensitivity mosaic image.

[0542] At step S383, the interpolation section 201-B discriminateswhether or not the color of the noticed pixel for the third time is G.If the interpolation section 201-B discriminates that the color of thenoticed pixel for the third time is G, then the processing advances tostep S384. At step S384, the interpolation section 201-B executes thevertical direction selective smoothing process using four pixelspositioned upwardly, downwardly, leftwardly and rightwardly in theneighborhood of the noticed pixel for the third time to calculate asmoothed value α. At step S385, the interpolation section 201-Bdetermines the smoothed value α calculated at step S384 as a pixel valuecorresponding to the noticed pixel for the third time of a B candidateimage. The processing returns to step S381.

[0543] It is to be noted that, if it is discriminated at step S383 thatthe color of the noticed pixel for the third time is not G, then theprocessing returns to step S381 skipping the steps S384 and S385.

[0544] Thereafter, the processing at steps S381 to S385 is repeateduntil it is discriminated at step S381 that all pixels of the color andsensitivity mosaic image have been used as a noticed pixel for the thirdtime. When it is discriminated at step S381 that all pixels of the colorand sensitivity mosaic image have been used as a noticed pixel for thethird time, the B candidate image production process is ended.

[0545] The G candidate image production process executed by themonochromatic image production section 183 is described with referenceto a flow chart of FIG. 110. It is to be noted that, for the convenienceof description, the component of the monochromatic image productionsection 183 which corresponds to the interpolation section 201 of themonochromatic image production section 182 is hereinafter referred to asinterpolation section 201-G.

[0546] At step S391, the interpolation section 201-G discriminateswhether or not all pixels of the color and sensitivity mosaic image havebeen used as a noticed pixel for the first time. If the interpolationsection 201-G discriminates that all pixels have not been used as anoticed pixel for the first time, then the processing advances to stepS392. At step S392, the interpolation section 201-G determines one byone pixel as a noticed pixel for the first time beginning with the leftlowermost pixel and ending with the right uppermost pixel of the colorand sensitivity mosaic image.

[0547] At step S393, the interpolation section 201-G discriminateswhether or not the color of the noticed pixel for the first time is G.If the interpolation section 201-G discriminates that the color of thenoticed pixel for the first time is G, then the processing advances tostep S394. At step S394, the interpolation section 201-G executes theoblique direction selective smoothing process using four pixelspositioned obliquely in the neighborhood of the noticed pixel for thefirst time to calculate a smoothed value α. At step S395, theinterpolation section 201-G applies the sum of the pixel value of thenoticed pixel for the first time and the smoothed value α calculated atstep S394 to a synthetic sensitivity compensation LUT (a syntheticsensitivity compensation LUT similar to that described with reference toFIGS. 90 to 92) built therein and determines the resulting value as apixel value corresponding to the noticed pixel for the first time of a Gcandidate image. The processing returns to step S391.

[0548] It is to be noted that, if it is discriminated at step S393 thatthe color of the noticed pixel for the first time is not G, then theprocessing returns to step S391 skipping the steps S394 and S395.

[0549] Thereafter, the processing at steps S391 to S395 is repeateduntil it is discriminated at step S391 that all pixels of the color andsensitivity mosaic image have been used as a noticed pixel for the firsttime. When it is discriminated at step S391 that all pixels of the colorand sensitivity mosaic image have been used as a noticed pixel for thefirst time, the processing advances to step S396.

[0550] At step S396, the interpolation section 201-G discriminateswhether or not all pixels of the color and sensitivity mosaic image havebeen used as a noticed pixel for the second time. If the interpolationsection 201-G discriminates that all pixels have not been used as anoticed pixel for the second time, then the processing advances to stepS397. At step S397, the interpolation section 201-G determines one byone pixel as a noticed pixel for the second time beginning with the leftlowermost pixel and ending with the right uppermost pixel of the colorand sensitivity mosaic image.

[0551] At step S398, the interpolation section 201-G discriminateswhether or not the color of the noticed pixel for the second time is G.If the interpolation section 201-G discriminates that the color of thenoticed pixel for the second time is not G, then the processing advancesto step S399. At step S399, the interpolation section 201-G executes thevertical direction selective smoothing process using four pixelspositioned upwardly, downwardly, leftwardly and rightwardly in theneighborhood of the noticed pixel for the second time to calculate asmoothed value α. At step S400, the interpolation section 201-Gdetermines the smoothed value α calculated at step S399 as a pixel valuecorresponding to the noticed pixel for the second time of the Gcandidate image. The processing returns to step S396.

[0552] It is to be noted that, if it is discriminated at step S398 thatthe color of the noticed pixel for the second time is R, then theprocessing returns to step S396 skipping the steps S399 and S400.

[0553] Thereafter, the processing at steps S396 to S400 is repeateduntil it is discriminated at step S396 that all pixels of the color andsensitivity mosaic image have been used as a noticed pixel for thesecond time. When it is discriminated at step S396 that all pixels ofthe color and sensitivity mosaic image have been used as a noticed pixelfor the second time, the R candidate image production process is ended.

[0554] Incidentally, as described hereinabove, in the fourth demosaicprocess, a luminance image and monochromatic images are produced from acolor and sensitivity mosaic image, and all colors are restored makinguse of the correlation between the luminance and the color components torestore all pixels having a uniform sensitivity and all colorcomponents. However, the luminance image to be produced first may have abiased spectral characteristic only if color information to be restoredhas the correlation and the signal can be restored with a highresolution. For example, the characteristic of a color mosaicarrangement of a color and sensitivity mosaic image that it includes anumber of pixels of G equal to twice that of pixels of R or pixels of Blike a Bayer arrangement may be utilized to produce an image of a Gcomponent in place of a luminance image, and the correlation between Gand R or between G and B may be utilized to produce an image of an Rcomponent and an image of a B component.

[0555] To execute such processing as just described, the imageprocessing section 7 may be configured in such a manner as shown in FIG.110. A luminance image production section 221 executes processingsimilar to that of the interpolation section 201 (FIG. 84) of themonochromatic image production section 182 in the fourth example of theconfiguration of the image processing section 7 to produce an outputimage G. Monochromatic image production sections 222 and 223 executeprocessing similar to that of the monochromatic image productionsections 182 and 184 in the fourth example of the configuration of theimage processing section 7 to produce an output image R and an outputimage B, respectively.

[0556] Description of the examples of the configuration of the imageprocessing section 7 for executing the first to fourth demosaicprocesses is ended therewith.

[0557] It is to be noted that, while the series of processes describedabove can be executed by hardware, it may otherwise be executed bysoftware. Where the series of processes is executed by software, aprogram which constructs the software is installed from a recordingmedium into a computer incorporated in hardware for exclusive use or,for example, a personal computer for universal use which can executevarious functions by installing various programs.

[0558] The recording medium is formed as a package medium such as, asshown in FIG. 1, a magnetic disc 16 (including a floppy disc), anoptical disc 17 (including a CD-ROM (Compact Disc-Read Only Memory) anda DVD (Digital Versatile Disc)), or a magneto-optical disc 18 (includingan MD (Mini Disc)), or a semiconductor memory 19 which has the programrecorded thereon or therein and is distributed to provide the program toa user separately from a computer. Else, the recording medium is formedas a ROM, a hard disc or the like in which the program is recorded andwhich is provided to a user in a state wherein the program isincorporated in a computer.

[0559] It is to be noted that, in the present specification, the stepswhich describe the program recorded in a recording medium may be butneed not necessarily be processed in a time series in the order asdescribed, and include processes which are executed in parallel orindividually without being processed in a time series.

INDUSTRIAL APPLICABILITY

[0560] As described above, according to the present invention, a colorand sensitivity mosaic image can be picked up which can be convertedinto a color image signal of a wide dynamic range by performing apredetermined image process therefor.

[0561] the pixel value is within the range between the threshold values,then the processing advances to step S34.

[0562] At step S34, the validity discrimination section 63 sets thediscrimination information of the noticed pixel as valid. The processingreturns to step S31.

[0563] If it is discriminated at step S33 that the pixel value of thenoticed pixel of the color and sensitivity mosaic image is not withinthe range between the threshold values, then the processing advances tostep S35. At step S35, the validity discrimination section 63discriminates whether or not the pixel value of the noticed pixel of thecolor and sensitivity mosaic image is equal to or higher than thethreshold level θ_(H) of the saturation level. If the validitydiscrimination section 63 discriminates that the pixel value is higherthan the threshold value θ_(H) of the saturation level, then theprocessing advances to step S36.

[0564] At step S36, the validity discrimination section 63 refers to thesensitivity mosaic pattern information to discriminate whether or notthe noticed pixel has the sensitivity S0. If the validity discriminationsection 63 discriminates that the noticed pixel has the sensitivity S0,then the processing advances to step S34. If the validity discriminationsection 63 discriminates that the noticed pixel does not have thesensitivity S0, then the processing advances to step S37.

[0565] At step S37, the validity discrimination section 63 sets thediscrimination information of the noticed pixel as invalid. Theprocessing returns to step S31.

[0566] If it is discriminated at step S35 that the pixel value of thenoticed pixel of the color and sensitivity mosaic image is not equal toor higher than the threshold value θ_(H), of the saturation level, thenthe processing advances to step S38. At step S38, the validitydiscrimination section 63 refers to the sensitivity mosaic patterninformation to discriminate whether or not the noticed pixel has thesensitivity S1. If the validity discrimination section 63 discriminatesthat the noticed pixel has the sensitivity S1, then the processingadvances to step S34. However, if the validity discrimination section 63discriminates that the noticed pixel does not have the sensitivity S1,then the processing advances to step S37.

[0567] Thereafter, the processing at steps S31 to S38 is repeated untilit is discriminated at step S31 that all pixels have been used as anoticed pixel. When it is discriminated at step S31 that all pixels havebeen used as a noticed pixel, the processing returns to step S13 of FIG.51.

[0568] At step S13, the missing interpolation section 64 performs amissing interpolation process for the sensitivity-compensated color andsensitivity mosaic image based on the discrimination information fromthe validity discrimination section 63 and supplies a resulting colormosaic image M to the color interpolation section 52.

[0569] Details of the missing interpolation process are described withreference to a flow chart of FIG. 54. At step S41, the missinginterpolation section 64 discriminates whether or not all pixels of thesensitivity-compensated color and sensitivity mosaic image have beenused as a noticed pixel. If the missing interpolation section 64discriminates that all pixels have not been used as a noticed pixel,then the processing advances to step S42. At step S42, the missinginterpolation section 64 determines one by one pixel as a noticed pixelbeginning with the left lowermost pixel and ending with the rightuppermost pixel of the sensitivity-compensated color and sensitivitymosaic image.

[0570] At step S43, the missing interpolation section 64 discriminateswhether or not the discrimination information of the noticed pixel isinvalid. If the missing interpolation section 64 discriminates that thediscrimination information is invalid, then the processing advances tostep S44.

[0571] At step S44, the missing interpolation section 64 refers to thecolor mosaic pattern information to discriminate the type of the colorof the noticed pixel (in the present case, one of the colors of R, G andB), detect, from among neighboring pixels with the noticed pixel (forexample, in the present case, 5×5 pixels centered at the noticed pixel),those pixels which have the same color and whose discriminationinformation is valid, and extracts the pixel values of the detectedpixels (hereinafter referred to as reference pixels).

[0572] At step S45, the missing interpolation section 64 acquires anumber of filter coefficients set in advance corresponding to relativepositions of the reference pixels to the noticed pixel, the number beingequal to the number of the reference pixels. At step S46, the missinginterpolation section 64 multiplies the pixel values of the referencepixels by the corresponding filter coefficients and arithmeticallyoperates the sum total of the products. Further, the missinginterpolation section 64 divides the sum total of the products by thesum total of the used filter coefficients and determines the quotient asa pixel value of the noticed pixel of the color mosaic image M.

[0573] The processing returns to step S41 so that the processing atsteps S41 to 46 is repeated until it is discriminated at step S41 thatall pixels have been used as a noticed pixel. When it is discriminatedat step S41 that all pixels have been used as a noticed pixel, theprocessing returns to step S2 of FIG. 50.

[0574] At step S2, the color interpolation section 52 performs a colorinterpolation process for the color mosaic image M obtained by thesensitivity uniformization process at step S1 described above based onthe color mosaic pattern information to produce output images R, G andB.

[0575] Details of the color interpolation process are described withreference to a flow chart of FIG. 55. At step S51, the gradationconversion section 71 performs a gradation modulation process for thecolor mosaic image M (more particularly, raises the pixel values of themodulated color mosaic image Mg to the γth power) to produce a modulatedcolor mosaic image Mg and supplies the modulated color mosaic image Mgto the color difference image production sections 72 and 73 and theluminance image production section 74.

[0576] At step S52, the color difference image production section 72uses the modulated color mosaic image Mg from the gradation conversionsection 71 to produce a color difference image C and supplies the colordifference image C to the luminance image production section 0.74 andthe color space conversion section 75. Meanwhile, the color differenceimage production section 73 uses the modulated color mosaic image Mgfrom the gradation conversion section 71 to produce a color differenceimage D and supplies the color difference image D to the luminance imageproduction section 74 and the color space conversion section 75.

[0577] The first process of the color difference image productionsection 72 producing a color difference image C is described withreference to a flow chart of FIG. 56. At step S61, the smoothingsections 81 and 82 discriminate whether or not all pixels of themodulated color mosaic image Mg have been used as a noticed pixel. Ifthe smoothing sections 81 and 82 discriminate that all pixels have notbeen used as a noticed pixel, then the processing advances to step S62.At step S62, the smoothing sections 81 and 82 determine one by one pixelas a noticed pixel beginning with the left lowermost pixel and endingwith the right uppermost pixel of the modulated color mosaic image Mg.

[0578] At step S63, the smoothing section 81 refers to the color mosaicpattern information to detect, from among neighboring pixels with thenoticed pixel (for example, 5×5 pixels centered at the noticed pixel),those pixels which have an R component, and extracts the pixel values ofthe detected pixels (hereinafter referred to as reference pixels).Meanwhile, also the smoothing section 82 similarly refers to the colormosaic pattern information to detect, from among neighboring pixels withthe noticed pixel, those pixels which have a G component, and extractsthe pixel values of the detected pixels.

[0579] At step S64, the smoothing section 81 acquires a number of filtercoefficients set in advance corresponding to relative positions of thereference pixels having an R component to the noticed pixel, the numberbeing equal to the number of the reference pixels. Meanwhile, also thesmoothing section 82 similarly acquires a number of filter coefficientsset in advance corresponding to relative positions of the referencepixels having a G component to the noticed pixel, the number being equalto the number of the reference pixels.

[0580] At step S65, the smoothing section 81 multiplies the pixel valuesof the reference pixels having an R component by the correspondingfilter coefficients and arithmetically operates the sum total of theproducts. Further, the smoothing section 81 divides the sum total of theproducts by the sum total of the used filter coefficients and determinesthe quotient as a pixel value corresponding to the noticed pixel of animage R′ which includes only smoothed R components. Meanwhile, also thesmoothing section 82 similarly multiplies the pixel values of thereference pixels having a G component by the corresponding filtercoefficients and arithmetically operates the sum total of the products.Further, the smoothing section 82 divides the sum total of the productsby the sum total of the used filter coefficients and determines thequotient as a pixel value corresponding to the noticed pixel of an imageG′ which includes only smoothed G components.

[0581] At step S66, the subtractor 83 subtracts the pixel valuecorresponding to the noticed pixel of the image R′ which includes onlysmoothed R components from the smoothing section 81 from the pixel valuecorresponding to the noticed pixel of the image G′ which includes onlysmoothed G components from the smoothing section 82 and determines thedifference as a pixel value corresponding to the noticed pixel of acolor difference image C.

[0582] The processing returns to step S61 so that the processing atsteps S61 to S66 is repeated until it is discriminated at step S61 thatall pixels have been used as a noticed pixel. When it is discriminatedat step S61 that all pixels have been used as a noticed pixel, theprocessing returns to step S53 of FIG. 55.

[0583] It is to be noted that, since the processing of the colordifference image production section 73 when it produces a colordifference image D is similar to the first process of the colordifference image production section 72 when it produces the colordifference image C described above, description of the processing isomitted.

[0584] At step S53, the luminance image production section 74 produces aluminance image L using the modulated mosaic image Mg and the colordifference signals C and D and supplies the luminance image L to thecolor space conversion section 75.

[0585] Details of the luminance image production process of theluminance image production section 74 are described with reference to aflow chart of FIG. 57. At step

[0586]FIG. 1

[0587]7 . . . Image processing section

[0588]9 . . . Memory

[0589]11 . . . Video encoder

[0590]12 . . . Display

[0591]13 . . . Operation inputting section

[0592]14 . . . Control section

[0593]15 . . . Drive

[0594]FIG. 2, from Left

[0595] Image pickup process

[0596] Color and sensitivity mosaic image

[0597] Image process

[0598] Output image

[0599]FIG. 23, from Above

[0600] Exposure period

[0601] Charge sweeping out instruction

[0602] Charge transfer instruction

[0603] Charge reading out instruction 1

[0604] Accumulated charge amount 1

[0605] Charge reading out instruction 2

[0606] Accumulated charge amount 2

[0607]FIG. 24, from Above

[0608] Exposure period

[0609] Charge sweeping out instruction

[0610] Charge transfer instruction

[0611] Charge reading out instruction 1

[0612] Accumulated charge amount 1

[0613] Charge reading out instruction 2

[0614] Accumulated charge amount 2

[0615]FIG. 34, from Left

[0616] Color and sensitivity mosaic image

[0617] Sensitivity uniformization process

[0618] Color mosaic image M

[0619] Color interpolation process

[0620]FIG. 35, from Above

[0621] Mosaic arrangement

[0622] Validity discrimination result

[0623]FIG. 36, from Above

[0624] Mosaic arrangement

[0625] Validity discrimination result

[0626]FIG. 37, from Above

[0627] Mosaic arrangement

[0628] Validity discrimination result

[0629]FIG. 38

[0630] Mosaic arrangement

[0631]FIG. 39

[0632] Mosaic arrangement

[0633]FIG. 40, from Left

[0634] Color and sensitivity mosaic image

[0635] Sensitivity uniformization process

[0636] Color mosaic image M

[0637] Color interpolation process

[0638]FIG. 41, from Above

[0639] Mosaic arrangement

[0640] Validity discrimination result

[0641]FIG. 42, from Above

[0642] Mosaic arrangement

[0643] Validity discrimination result

[0644]FIG. 43

[0645] Mosaic arrangement

[0646]FIG. 44

[0647] Mosaic arrangement

[0648]FIG. 45

[0649] Left top . . . Color mosaic pattern information

[0650] Left middle . . . Color and sensitivity mosaic image

[0651] Left bottom . . . Sensitivity mosaic pattern information

[0652]51 . . . Sensitivity uniformization section

[0653] Right to 51 . . . Color mosaic image M

[0654]52 . . . Color interpolation section

[0655] Right top . . . Output image R

[0656] Right middle . . . Output image G

[0657] Right bottom . . . Output image B

[0658]FIG. 46

[0659]61 . . . Sensitivity compensation section

[0660] Left to 61 . . . Color and sensitivity mosaic image

[0661] Above 61 . . . Sensitivity mosaic pattern information

[0662] Right to 61 . . . Sensitivity-compensated color and sensitivitymosaic image

[0663]62 . . . Relative sensitivity value LUT

[0664]63 . . . Validity discrimination section

[0665] Right to 63 . . . Discrimination information

[0666]64 . . . Missing interpolation section

[0667] Above 64 . . . color mosaic pattern information

[0668] Right to 64 . . . Color mosaic image M

[0669]FIG. 47

[0670]71 . . . Gradation conversion section

[0671] Left to 71 . . . Color mosaic image M

[0672] Right to 71 . . . Modulated color mosaic image Mg

[0673]72 . . . Color difference image production section

[0674]73 . . . Color difference image production section

[0675] Left to 73 . . . Color mosaic pattern information

[0676]74 . . . Luminance image production section

[0677] Right to 74, top . . . Color difference image C

[0678] Right to 74, middle . . . Luminance image L

[0679] Right to 74, bottom . . . Color difference image D

[0680]75 . . . Color space conversion section

[0681]76 . . . Gradation reverse conversion section

[0682] Right to 76 . . . Output image R

[0683]77 . . . Gradation reverse conversion section

[0684] Right to 77 . . . Output image G

[0685]78 . . . Gradation reverse conversion section

[0686] Right to 78 . . . Output image B

[0687]FIG. 48

[0688] Left top . . . Modulated color mosaic image Mg

[0689] Left bottom . . . Color mosaic pattern information

[0690]81 . . . Smoothing section

[0691]82 . . . Smoothing section

[0692]83 . . . Subtractor

[0693] Right to 83 . . . Color difference image C

[0694]FIG. 49

[0695] Left top . . . Color difference image C

[0696] Left second top . . . Modulated color mosaic image Mg

[0697] Left second bottom . . . Color difference image D

[0698] Left bottom . . . Color mosaic pattern information

[0699]91 . . . Luminance calculation section

[0700] Right to 91 . . . Luminance candidate image Lc

[0701]92 . . . Noise removal section

[0702] Right to 92 . . . Luminance image L

[0703]FIG. 50

[0704] Top . . . Start

[0705] S1 . . . Sensitivity uniformization process

[0706] S2 . . . Color interpolation process

[0707] Bottom . . . End

[0708]FIG. 51

[0709] Top . . . Start of first sensitivity uniformization process

[0710] S11 . . . Sensitivity compensation process

[0711] S12 . . . Validity discrimination process

[0712] S13 . . . Missing interpolation process

[0713] Bottom . . . Return

[0714]FIG. 52

[0715] Top . . . Start of sensitivity compensation process

[0716] S21 . . . All pixels used as noticed pixel?

[0717] Right to S21 . . . Return

[0718] S22 . . . Decide noticed pixel

[0719] S23 . . . Refer to relative sensitivity value LUT to acquirerelative sensitivity value S of noticed pixel

[0720] S24 . . . Divide pixel value of noticed pixel by relativesensitivity value S

[0721]FIG. 53

[0722] Top . . . Start of validity discrimination process

[0723] S31 . . . All pixels used as noticed pixel?

[0724] Right to S31 . . . Return

[0725] S32 . . . Decide noticed pixel

[0726] S33 . . . Threshold value θ_(L)<pixel value of noticedpixel<threshold value θ_(H)?

[0727] S34 . . . Set discrimination information as “valid”

[0728] S35 . . . Threshold value θ_(H)<pixel value of noticed pixel?

[0729] S36 . . . Sensitivity of noticed pixel S0?

[0730] S37 . . . Set discrimination information as “invalid”

[0731] S38 . . . Sensitivity of noticed pixel S1?

[0732]FIG. 54

[0733] Top . . . Start of missing interpolation process

[0734] S41 . . . All pixels used as noticed pixel?

[0735] Right to S41 . . . Return

[0736] S42 . . . Decide noticed pixel

[0737] S43 . . . Pixel value of noticed pixel “invalid”?

[0738] S44 . . . Detect pixels (reference pixels) whose color is same asthat of noticed pixel and whose discrimination information is “valid”within predetermined range centered at noticed pixel

[0739] S45 . . . Acquire filter coefficients determined in accordancewith relative positions of reference pixels to noticed pixel

[0740] S46 . . . Divide sum total of products of pixel values ofreference pixels and filter coefficients by sum total of used filtercoefficients to acquire smoothed pixel value

[0741]FIG. 55

[0742] Top . . . Start of color interpolation process

[0743] S51 . . . Gradation conversion process

[0744] S52 . . . Color difference image production process

[0745] S53 . . . Luminance image production process

[0746] S54 . . . Color space conversion process

[0747] S55 . . . Gradation reverse conversion process

[0748] Bottom . . . Return

[0749]FIG. 56

[0750] Top . . . Start of color difference image C production process

[0751] S61 . . . All pixels of modulated color mosaic image Mg used asnoticed pixel?

[0752] Right to S61 . . . Return

[0753] S62 . . . Decide noticed pixel of modulated color mosaic image

[0754] S63 . . . Detect pixels (reference pixels) having R component (orG component) within predetermined range centered at noticed pixel Mg(x,y)

[0755] S64 . . . Acquire filter coefficients determined in accordancewith relative positions of reference pixels to noticed pixel

[0756] S65 . . . Divide sum total of products of pixel values ofreference pixels and filter coefficients by sum total of used filtercoefficients to arithmetically operate R′ component (or G′ component) ofpixel corresponding to noticed pixel

[0757] S66 . . . Calculate pixel value of color difference image Ccorresponding to noticed pixel, R′−G′

[0758]FIG. 57

[0759] Top . . . Start of luminance image production process

[0760] S71 . . . All pixels of modulated color mosaic image Mg used asnoticed pixel?

[0761] S72 . . . Decide pixel of coordinates (x, y) as noticed pixel

[0762] S73 (Above S74 and S76) . . . Which one of RGB components doesnoticed pixel Mg(x, y) of modulated color mosaic image Mg have?

[0763] S74 . . . Pixel Lc(x, y) of luminance candidate image Lc=3Mg(x,y)−2C(x, y)+D(x, y)

[0764] S73 (Below S74 and S76) . . . Pixel Lc(x, y) of luminancecandidate image Lc=3Mg(x, y)+C(x, y)+D(x, y)

[0765] S76 . . . Pixel Lc(x, y) of luminance candidate image Lc=3Mg(x,y)+C(x, y)−2D(x, y)

[0766] S77 . . . All pixels of luminance candidate image Lc used asnoticed pixel?

[0767] Right to S77 . . . Return

[0768] S78 . . . Decide pixel of coordinates (x, y) as noticed pixel

[0769] S79 . . . Calculate gradient ∇Lc (x, y) of noticed pixel Lc (x,y)

[0770] S80 . . . Calculate smoothed component Hh in horizontal directionand smoothed component Hv in vertical direction for noticed pixel Lc(x,y)

[0771] S81 . . . Calculate smoothed contribution wh in horizontaldirection and smoothed contribution wv in vertical direction based onmagnitude of ∇Lc (x, y)

[0772] S82 . . . Add smoothed component to pixel Lc(x, y) of luminancecandidate image Lc in accordance with contributions to produce pixelL(x, y) of luminance image L

[0773]FIG. 58

[0774] Top . . . Start of color space conversion process

[0775] S91 . . . All pixels used as noticed pixel?

[0776] S92 . . . Decide noticed pixel

[0777] S93 . . . Calculate RGB components of pixel of modulated image

Rg(x, y)=(L(x, y)+2C(x, y)−D(x, y))/3

Gg(x, y)=(L(x, y)−C(x, y)−D(x, y))/3

Bg(x, y)=(L(x, y)−C(x, y)+2D(x, y))/3

[0778] Bottom . . . Return

[0779]FIG. 59

[0780] Top . . . Color mosaic pattern information

[0781] Left . . . Color and sensitivity mosaic image

[0782] Bottom . . . Sensitivity mosaic pattern information

[0783] Right . . . Color mosaic image M

[0784]101-1 to 101-4 . . . Interpolation section

[0785]103 . . . Synthetic sensitivity compensation section

[0786]104 . . . Synthetic sensitivity compensation LUT

[0787]FIG. 60

[0788] Top . . . Start of second sensitivity uniformization process

[0789] S101 . . . All pixels used as noticed pixel?

[0790] Right to S101 . . . Return

[0791] S102 . . . Decide noticed pixel

[0792] S103 . . . Interpolation process

[0793] S104 . . . Add interpolation value

[0794] S105 . . . Synthetic sensitivity compensation process

[0795]FIG. 61

[0796] Top . . . Start of interpolation process

[0797] S111 . . . Detect pixels (reference pixels) which have designatedcolor and have sensitivity S0 within predetermined range centered atnoticed pixel

[0798] S112 . . . Acquire filter coefficients determined in accordancewith relative positions of reference pixels to noticed pixel

[0799] S113 . . . Divide sum total of products of pixel values ofreference pixels and filter coefficients by sum total of used filtercoefficients to acquire smoothed pixel value

[0800] Bottom . . . Return

[0801]FIG. 62

[0802] Top . . . Start of color difference image production process

[0803] S121 . . . All pixels of modulated color mosaic image Mg used asnoticed pixel?

[0804] Right to S121 . . . Return

[0805] S122 . . . Decide one of pixels of modulated color mosaic imageas noticed pixel Mg(x, y)

[0806] S123 . . . Arithmetically operate image gradient vector g atcoordinates (x, y)

[0807] S124 . . . Detect reference pixels having R component (or Gcomponent) within predetermined range centered at noticed pixel Mg(x, y)

[0808] S125 . . . Calculate vectors n from noticed pixel Mg(x, y) toreference pixels

[0809] S126 . . . Calculate significances ω of reference pixels usingimage gradient vector g

[0810] S127 . . . Acquire filter coefficients for relative positions (i,j) of reference pixels to noticed pixel Mg(x, y)

[0811] S128 . . .  Calculate sum total of products of reference pixels,significances ω and filter coefficients

[0812]  Calculate sum total of products of significances ω and filtercoefficients

[0813] S129 . . . Calculate R′ component (or G′ component) of noticedpixel Mg(x, y)

[0814] S130 . . . Calculate pixel value of color difference image C

[0815]FIG. 63

[0816] Top . . . Start of image gradient vector g calculation process

[0817] S141 . . . Noticed pixel Mg(x, v) has G component?

[0818] S142 . . . Interpolate G components of four upwardly, downwardly,leftwardly and rightwardly adjacent pixels

[0819] S143 . . . Calculate image gradient vector g

[0820] S144 . . . Acquire G components of four upwardly, downwardly,leftwardly and rightwardly adjacent pixels

[0821] Bottom . . . Return

[0822]FIG. 64

[0823] Left top . . . Color mosaic pattern information

[0824] Left middle . . . Color and sensitivity mosaic image

[0825] Left bottom . . . Sensitivity mosaic pattern information

[0826] Top . . . Updated color mosaic pattern information

[0827] Right top . . . Output image R

[0828] Right middle . . . Output image G

[0829] Right bottom . . . Output image B

[0830]111 . . . Sensitivity uniformization section

[0831] Right to 111 . . . Color mosaic image M

[0832]112 . . . Color interpolation section

[0833]FIG. 65

[0834]121 . . . Sensitivity compensation section

[0835] Left to 121 . . . Color and sensitivity mosaic image

[0836] Above 121 . . . Sensitivity mosaic pattern information

[0837] Right to 121 . . . Sensitivity-compensated color and sensitivitymosaic image

[0838]122 . . . Relative sensitivity value LUT

[0839]123 . . . Validity discrimination section

[0840] Right to 123 . . . Discrimination information

[0841]124 . . . Missing interpolation section

[0842] Above 124 . . . Color mosaic pattern information

[0843] Right to 124, upper . . . Updated color mosaic patterninformation

[0844] Right to 124, lower . . . Color mosaic image M

[0845]FIG. 66

[0846] Top . . . Start of missing interpolation process

[0847] S151 . . . All pixels used as noticed pixel?

[0848] Right to S151 . . . Return

[0849] S152 . . . Decide noticed pixel

[0850] S153 . . . Discrimination information of noticed pixel “invalid”?

[0851] S154 . . . Smooth neighboring valid pixels having G component tointerpolate G component of noticed pixel

[0852] S155 . . . Update color mosaic pattern information

[0853]FIG. 67

[0854] Left top . . . Color mosaic pattern information

[0855] Left bottom . . . Color and sensitivity mosaic image

[0856] Bottom . . . Sensitivity mosaic pattern information

[0857] Right top . . . Updated color mosaic pattern information

[0858] Right bottom . . . Color mosaic image M

[0859]131 . . . Interpolation color determination section

[0860]132-1 to 132-4 . . . Interpolation section

[0861]134 . . . Sensitivity compensation section

[0862]135 . . . Synthetic sensitivity compensation LUT

[0863]FIG. 68

[0864] Top . . . Start of sensitivity uniformization process

[0865] S161 . . . All pixels used as noticed pixel?

[0866] Right to S161 . . . Return

[0867] S162 . . . Decide noticed pixel

[0868] S163 . . . Interpolation color determination process

[0869] S164 . . . Interpolation process for each sensitivity

[0870] S165 . . . Integrate interpolation values

[0871] S166 . . . Synthetic sensitivity compensation process

[0872]FIG. 69

[0873] Top . . . Start of interpolation color determination process

[0874] S171 . . . Color of noticed pixel discriminated?

[0875] S172 . . . Determine interpolation color as G

[0876] S173 . . . Determine interpolation color as B

[0877] S174 . . . Determine interpolation color as R

[0878] Bottom . . . Return

[0879]FIG. 70, from Left, from Above

[0880] Color and sensitivity mosaic image

[0881] By-sensitivity-basis color interpolation process

[0882] Sensitivity mosaic image Ms

[0883] Sensitivity uniformization process

[0884] Sensitivity uniformization process

[0885] Sensitivity uniformization process

[0886]FIG. 71, from Left

[0887] Color and sensitivity mosaic image

[0888] Extraction process

[0889] Color mosaic image McS1

[0890] Color interpolation process

[0891]FIG. 72, from Left

[0892] Insertion process

[0893] Sensitivity mosaic image MsR

[0894]FIG. 73

[0895] Left top . . . Color mosaic pattern information

[0896] Left middle . . . Color and sensitivity mosaic image

[0897] Left bottom . . . Sensitivity mosaic pattern information

[0898]151 . . . By-sensitivity-basis color interpolation section

[0899]152 . . . Sensitivity uniformization section

[0900] Left to 152 . . . Sensitivity mosaic image MsR

[0901] Right to 152 . . . Output image R

[0902]153 . . . Sensitivity uniformization section

[0903] Left to 153 . . . Sensitivity mosaic image MsG

[0904] Right to 153 . . . Output image G

[0905]154 . . . Sensitivity uniformization section

[0906] Left to 154 . . . Sensitivity mosaic image MsB

[0907] Right to 154 . . . Output image B

[0908]FIG. 74

[0909] Left top . . . Color mosaic pattern information

[0910] Left bottom . . . Color and sensitivity mosaic image

[0911]161 . . . Extraction section

[0912] Above 161 . . . Sensitivity mosaic pattern information

[0913] Right to 161 . . . Color mosaic pattern information ofsensitivity ‘Si’

[0914]162 . . . Color interpolation section

[0915] Below 162 . . . Color mosaic image McSi of sensitivity ‘Si’

[0916]163 . . . Insertion section

[0917] Above 163 . . . Original position information of sensitivity ‘Si’

[0918] Left to 163 . . . Image RSi of sensitivity ‘Si’

[0919] Right to 163 . . . Sensitivity mosaic image MsR

[0920]164 . . . Insertion section

[0921] Left to 164 . . . Image GSi of sensitivity ‘Si’

[0922] Right to 164 . . . Sensitivity mosaic image MsG

[0923]165 . . . Insertion section

[0924] Left to 165 . . . Image BSi of sensitivity ‘Si’

[0925] Right to 165 . . . Sensitivity mosaic image MsB

[0926]FIG. 75

[0927]171 . . . Local sum calculation section

[0928] Left to 171 . . . Sensitivity mosaic image MsR

[0929]172 . . . Synthetic sensitivity compensation section

[0930] Right to 172 . . . Output image R

[0931]173 . . . Synthetic sensitivity compensation LUT

[0932]FIG. 76

[0933] Top . . . Start

[0934] S181 . . . By-sensitivity-basis color interpolation process

[0935] S182 . . . Sensitivity uniformization process

[0936] Bottom . . . End

[0937]FIG. 77

[0938] Top . . . Start of by-sensitivity-basis color interpolationprocess

[0939] S191 . . . All sensitivities designated?

[0940] S192 . . . Designate sensitivity Si

[0941] S193 . . . Extraction process

[0942] S194 . . . Color interpolation process

[0943] S195 . . . Insertion process

[0944] Bottom . . . Return

[0945]FIG. 80

[0946] Top . . . Start of sensitivity uniformization process

[0947] S201 . . . All pixels used as noticed pixel?

[0948] Right to S201 . . . Return

[0949] S202 . . . Decide noticed pixel

[0950] S203 . . . Local sum calculation process

[0951] S204 . . . Synthetic sensitivity compensation

[0952]FIG. 82

[0953] Top . . . Color mosaic pattern information

[0954] Left . . . Color and sensitivity mosaic image

[0955] Bottom . . . Sensitivity mosaic pattern information

[0956] Right top . . . Output image R

[0957] Right middle . . . Output image G

[0958] Right bottom . . . Output image B

[0959]181 . . . Luminance image production section

[0960] Right to 181 . . . Luminance image

[0961]182 . . . Monochromatic image production section

[0962]183 . . . Monochromatic image production section

[0963]184 . . . Monochromatic image production section

[0964]FIG. 83

[0965] Top . . . Color mosaic pattern information

[0966] Left . . . Color and sensitivity mosaic image

[0967] Bottom . . . Sensitivity mosaic pattern information

[0968] Right . . . Luminance image

[0969]191 . . . Estimation section

[0970]192 . . . Estimation section

[0971]193 . . . Estimation section

[0972] Right to 197 . . . Luminance candidate image

[0973]198 . . . Noise removal section

[0974]FIG. 84

[0975] Left top . . . Color mosaic pattern information

[0976] Left second top . . . Color and sensitivity mosaic image

[0977] Left second bottom . . . Sensitivity mosaic pattern information

[0978] Left bottom . . . Luminance image

[0979]201 . . . Interpolation section

[0980] Right to 201 . . . R candidate image

[0981]202 . . . Ratio value calculation section

[0982] Right to 202 . . . Ratio value information

[0983] Right to 203 . . . Output image R

[0984]FIG. 85

[0985] Top . . . Start

[0986] S211 . . . Luminance image production process

[0987] S212 . . . Monochromatic image production process

[0988] Bottom . . . End

[0989]FIG. 86

[0990] Top . . . Start of luminance image production process

[0991] S221 . . . All pixels used as noticed pixel?

[0992] S222 . . . Decide noticed pixel

[0993] S223 . . . RGB component estimation process

[0994] S224 . . . Arithmetically operate luminance candidate value

[0995] S225 . . . Noise removal process

[0996] Bottom . . . Return

[0997]FIG. 87

[0998] Top . . . Start of R component estimation process

[0999] S231 . . . Detect pixels (reference pixels) which have Rcomponent and sensitivity S0 within predetermined range centered atnoticed pixel

[1000] S232 . . . Divide sum total of products of reference pixels andcorresponding interpolation filter coefficients by sum total of usedinterpolation filter coefficients to acquire first quotient

[1001] S233 . . . Detect pixels (reference pixels) which have Rcomponent and sensitivity S1 within predetermined range centered atnoticed pixel

[1002] S234 . . . Divide sum total of products of reference pixels andcorresponding interpolation filter coefficients by sum total of usedinterpolation filter coefficients to acquire second quotient

[1003] S235 . . . Add first quotient and second quotient

[1004] S236 . . . Refer to synthetic sensitivity compensation LUT toacquire estimated value R′ of R component

[1005] Bottom . . . Return

[1006]FIG. 93

[1007] Top . . . Start of noise removal process

[1008] S241 . . . All pixels used as noticed pixel?

[1009] Right to S241 . . . Return

[1010] S242 . . . Decide noticed pixel

[1011] S243 . . . Acquire luminance candidate values of pixels upwardly,downwardly, leftwardly and rightwardly of noticed pixel

[1012] S244 . . . Direction selective smoothing process

[1013] S245 . . . Determine average value of luminance candidate valuesand smoothed value of noticed pixel as luminance value

[1014]FIG. 94

[1015] Top . . . Start of direction selective smoothing process

[1016] S251 . . . Arithmetically operate luminance gradient vector ofnoticed pixel

[1017] S252 . . . Arithmetically operate magnitude of luminance gradientvector

[1018] S253 . . . Arithmetically operate smoothed component inhorizontal direction and smoothed component in vertical direction

[1019] S254 . . . Arithmetically operate significance in horizontaldirection and significance in vertical direction in accordance withmagnitude of luminance gradient vector

[1020] S255 . . . Arithmetically operate smoothed value

[1021] Bottom . . . Return

[1022]FIG. 95

[1023] Top . . . Start of monochromatic image production process

[1024] S261 . . . Production of monochromatic candidate image

[1025] S262 . . . Ratio value calculation process

[1026] S263 . . . Multiply monochromatic candidate image by ratio valueto produce monochromatic image

[1027] Bottom . . . Return

[1028]FIG. 96

[1029] Top . . . Start of ratio value calculation process

[1030] S271 . . . All pixels used as noticed pixel?

[1031] Right to S271 . . . Return

[1032] S272 . . . Decide noticed pixel

[1033] S273 . . . Acquire monochromatic candidate values and luminancevalues of pixels within predetermined range centered at noticed pixel

[1034] S274 . . . Acquire smoothing filter coefficients corresponding torelative positions of neighboring pixels to noticed pixel

[1035] S275 . . . Arithmetically operate ratio value

[1036]FIG. 98

[1037]211 . . . Estimation section

[1038] Left to 211 . . . Color and sensitivity mosaic image

[1039] Above 211 . . . Color mosaic pattern information

[1040] Below 211 . . . Sensitivity mosaic pattern information

[1041] Right to 197 . . . Luminance candidate image

[1042]198 . . . Noise removal section

[1043] Right to 198 . . . Luminance image

[1044]FIG. 99

[1045] Top . . . Start of RGB component estimation process

[1046] S281 . . . Interpolation of estimated pixel value C0corresponding to noticed pixel

[1047] S282 . . . Interpolation of estimated pixel value C1corresponding to noticed pixel

[1048] S283 . . . Interpolation of estimated pixel value C2corresponding to noticed pixel

[1049] S284 . . . Interpolation of estimated pixel value C3corresponding to noticed pixel

[1050] S285 . . . Refer to synthetic sensitivity compensation LUT toacquire estimated values of RGB components corresponding to color andsensitivity of noticed pixel

[1051] Bottom . . . Return

[1052]FIG. 101

[1053] Top . . . Start of estimated pixel value C0 interpolation process

[1054] S291 . . . Arithmetically operate smoothed value α by verticaldirection selective smoothing process corresponding to noticed pixel

[1055] S292 . . . Add smoothed value α to pixel value of noticed pixelto obtain estimated pixel value C0

[1056] Bottom . . . Return

[1057]FIG. 103

[1058] Top . . . Start of estimated pixel value C1 interpolation process

[1059] S301 . . . Color of noticed pixel G?

[1060] S302 . . . Arithmetically operate smoothed value α by obliquedirection selective smoothing process corresponding to noticed pixel

[1061] S303 . . . Multiply smoothed value α by 2 to obtain estimatedpixel value C1

[1062] S304 . . . Arithmetically operate value a1 by vertical directionselective smoothing process corresponding to left upward pixel ofnoticed pixel

[1063] S305 . . . Arithmetically operate value a2 by vertical directionselective smoothing process corresponding to right downward pixel ofnoticed pixel

[1064] S306 . . .  Determine pixel value of left downward pixel ofnoticed pixel as value a0

[1065]  Determine pixel value of right upward pixel of noticed pixel asvalue a3

[1066] S307 . . . Apply values a0, a1, a2 and a3 to selective smoothingprocess to arithmetically operate smoothed value a′

[1067] S308 . . . Arithmetically operate value a0 by vertical directionselective smoothing process corresponding to left downward pixel ofnoticed pixel

[1068] S309 . . . Arithmetically operate value a3 by vertical directionselective smoothing process corresponding to right upward pixel ofnoticed pixel

[1069] S310 . . .  Determine pixel value of left upward pixel ofnoticed pixel as value a1

[1070]  Determine pixel value of right downward pixel of noticed pixelas value a2

[1071] S311 . . . Apply values a0, a1, a2 and a3 to selective smoothingprocess to arithmetically operate smoothed value a″

[1072] S312 . . . Add smoothed value a′ and smoothed value a″ to obtainestimated pixel value C1

[1073] Bottom . . . Return

[1074]FIG. 105

[1075] Top . . . Start of estimated pixel value C2 interpolation process

[1076] S321 . . . Color of noticed pixel G?

[1077] S322 . . . Arithmetically operate smoothed value a′ by verticaldirection selective smoothing process corresponding to pixel abovenoticed pixel

[1078] S323 . . . Arithmetically operate smoothed value a″ by verticaldirection selective smoothing process corresponding to pixel belownoticed pixel

[1079] S324 . . . Add average value of pixel value of pixel belownoticed pixel and smoothed value a′ and average value of pixel value ofpixel above noticed pixel and smoothed value a″ to obtain estimatedpixel value C2

[1080] S325 . . . Arithmetically operate value a1 by oblique directionselective smoothing process corresponding to left pixel of noticed pixel

[1081] S326 . . . Arithmetically operate value a2 by oblique directionselective smoothing process corresponding to right pixel of noticedpixel

[1082] S327 . . .  Determine pixel value of pixel below noticed pixelas value a0

[1083]  Determine pixel value of pixel above noticed pixel as value a3

[1084] S328 . . . Apply values a0, a1, a2 and a3 to selective smoothingprocess to arithmetically operate smoothed value a′

[1085] S329 . . . Arithmetically operate value a0 by oblique directionselective smoothing process corresponding to pixel below noticed pixel

[1086] S330 . . . Arithmetically operate value a3 by oblique directionselective smoothing process corresponding to pixel above noticed pixel

[1087] S331 . . .  Determine pixel value of left pixel of noticed pixelas value a1

[1088]  Determine pixel value of right pixel of noticed pixel as valuea2

[1089] S332 . . . Apply values a0, a1, a2 and a3 to selective smoothingprocess to arithmetically operate smoothed value a″

[1090] S333 . . . Add smoothed value a′ and smoothed value a″ to obtainestimated pixel value C2

[1091] Bottom . . . Return

[1092]FIG. 107

[1093] Top . . . Start of estimated pixel value C3 interpolation process

[1094] S341 . . . Color of noticed pixel G?

[1095] S342 . . . Arithmetically operate smoothed value a′ by verticaldirection selective smoothing process corresponding to right pixel ofnoticed pixel

[1096] S343 . . . Arithmetically operate smoothed value a″ by verticaldirection selective smoothing process corresponding to left pixel ofnoticed pixel

[1097] S344 . . . Add average value of pixel value of left pixel ofnoticed pixel and smoothed value a′ and average value of pixel value ofright pixel of noticed pixel and smoothed value a″ to obtain estimatedpixel value C3

[1098] S345 . . . Set estimated pixel value C3=0

[1099] Bottom . . . Return

[1100]FIG. 108

[1101] Top . . . Start of R candidate image production process

[1102] S351 . . . All pixels used as noticed pixel?

[1103] S352 . . . Decide noticed pixel

[1104] S353 . . . Color of noticed pixel R?

[1105] S354 . . . Arithmetically operate value α by vertical directionselective smoothing process corresponding to noticed pixel

[1106] S355 . . . Refer to synthetic sensitivity compensation LUT toacquire value corresponding to sum of pixel value of noticed pixel andvalue α and determine acquired value as candidate value for pixelcorresponding to noticed pixel of R candidate image

[1107] S356 . . . All pixels used as noticed pixel?

[1108] S357 . . . Decide noticed pixel

[1109] S358 . . . Color of noticed pixel B?

[1110] S359 . . . Arithmetically operate value α by oblique directionselective smoothing process corresponding to noticed pixel

[1111] S360 . . . Determine value α as candidate value for pixelcorresponding to noticed pixel of R candidate image

[1112] S361 . . . All pixels used as noticed pixel?

[1113] Right to S361 . . . Return

[1114] S362 . . . Decide noticed pixel

[1115] S363 . . . Color of noticed pixel G?

[1116] S364 . . . Arithmetically operate value α by vertical directionselective smoothing process corresponding to noticed pixel

[1117] S365 . . . Determine value α as candidate value for pixelcorresponding to noticed pixel of R candidate image

[1118]FIG. 109

[1119] Top . . . Start of B candidate image production process

[1120] S371 . . . All pixels used as noticed pixel?

[1121] S372 . . . Decide noticed pixel

[1122] S373 . . . Color of noticed pixel B?

[1123] S374 . . . Arithmetically operate value α by vertical directionselective smoothing process corresponding to noticed pixel

[1124] S375 . . . Refer to synthetic sensitivity compensation LUT toacquire value corresponding to sum of pixel value of noticed pixel andvalue α and determine acquired value as candidate value for pixelcorresponding to noticed pixel of B candidate image

[1125] S376 . . . All pixels used as noticed pixel?

[1126] S37-7 . . . Decide noticed pixel

[1127] S378 . . . Color of noticed pixel R?

[1128] S379 . . . Arithmetically operate value α by oblique directionselective smoothing process corresponding to noticed pixel

[1129] S380 . . . Determine value α as candidate value for pixelcorresponding to noticed pixel of B candidate image

[1130] S381 . . . All pixels used as noticed pixel?

[1131] Right to S381 . . . Return

[1132] S382 . . . Decide noticed pixel

[1133] S383 . . . Color of noticed pixel G?

[1134] S384 . . . Arithmetically operate value α by vertical directionselective smoothing process corresponding to noticed pixel

[1135] S385 . . . Determine value α as candidate value for pixelcorresponding to noticed pixel of B candidate image

[1136]FIG. 110

[1137] Top . . . Start of G candidate image production process

[1138] S391 . . . All pixels used as noticed pixel?

[1139] S392 . . . Decide noticed pixel

[1140] S393 . . . Color of noticed pixel G?

[1141] S394 . . . Arithmetically operate value α by oblique directionselective smoothing process corresponding to noticed pixel

[1142] S395 . . . Refer to synthetic sensitivity compensation LUT toacquire value corresponding to sum of pixel value of noticed pixel andvalue α and determine acquired value as candidate value for pixelcorresponding to noticed pixel of G candidate image

[1143] S396 . . . All pixels used as noticed pixel?

[1144] Right to S396 . . . Return

[1145] S397 . . . Decide noticed pixel

[1146] S398 . . . Color of noticed pixel G?

[1147] S399 . . . Arithmetically operate value α by vertical directionselective smoothing process corresponding to noticed pixel

[1148] S400 . . . Update candidate value for pixel corresponding tonoticed pixel of G candidate image with value α

[1149]FIG. 111

[1150] Left . . . Color and sensitivity mosaic image

[1151] Top . . . Color mosaic pattern information

[1152] Bottom . . . Sensitivity mosaic pattern information

[1153] Right top . . . Output image R

[1154] Right bottom . . . Output image G

[1155]221 . . . Luminance image production section

[1156] Right to 221 . . . Output image G

[1157]222 . . . Monochromatic image production section

[1158]223 . . . Monochromatic image production section

1. (As amended) An image pickup apparatus which includes photo-electricconversion means for photo-electrically converting an optical image of asubject to produce a color and sensitivity mosaic image wherein eachpixel has one of a plurality of color components and has one of aplurality of sensitivity characteristics to light intensity,characterized in that said photo-electric conversion means produces thecolor and sensitivity mosaic image wherein a plurality of pixels havingthe same color components and the same sensitivity characteristics arearranged in lattice arrangements and a plurality of pixels of at leastone kind from among the plurality of pixels having the same colorcomponent and having the same sensitivity characteristic are arranged soas not to neighbor with pixels of a different kind having the same colorcomponent but having a different sensitivity characteristic.
 2. (Asamended) An image pickup apparatus as set forth in claim 1,characterized in that said photo-electric conversion means produces thecolor and sensitivity mosaic image wherein a plurality of pixels havingthe same color components irrespective of the sensitivitycharacteristics are arranged in lattice arrangements.
 3. (As amended) Animage pickup apparatus as set forth in claim 2, characterized in thatsaid photo-electric conversion means produces the color and sensitivitymosaic image wherein a plurality of pixels having the same colorcomponents irrespective of the sensitivity characteristics are arrangedin square lattice arrangements.
 4. (As amended) An image pickupapparatus as set forth in claim 2, characterized in that the pluralityof color components are the three primary color components.
 5. (Asamended) An image pickup apparatus as set forth in claim 4,characterized in that said photo-electric conversion means produces thecolor and sensitivity mosaic image which has a Bayer arrangement whereattention is paid only to the color components.
 6. (As amended) An imagepickup apparatus as set forth in claim 1, characterized in that saidphoto-electric conversion means produces the color and sensitivitymosaic image wherein a plurality of pixels having the same sensitivitycharacteristics irrespective of the color components are arranged inlattice arrangements such that all of the color components included inthe color and sensitivity mosaic image exist in totaling five pixelsincluding an arbitrary pixel of the color and sensitivity mosaic imageand four pixels neighboring upwardly, downwardly, leftwardly andrightwardly of the arbitrary pixel.
 7. (As amended) An image pickupapparatus as set forth in claim 6, characterized in that saidphoto-electric conversion means produces the color and sensitivitymosaic image wherein a plurality of pixels having the same sensitivitycharacteristics irrespective of the color components are arranged insquare lattice arrangements.
 8. (As amended) An image pickup apparatusas set forth in claim 6, characterized in that the plurality of colorcomponents are the three primary color components.
 9. (As amended) Animage pickup apparatus as set forth in claim 8, characterized in thatsaid photo-electric conversion means produces the color and sensitivitymosaic image wherein the color components form a Bayer arrangement foreach of the sensitivity characteristics of the pixels.
 10. (As amended)An image pickup device for photo-electrically converting an opticalimage of a subject to produce a color and sensitivity mosaic imagewherein each pixel has one of a plurality of color components and one ofa plurality of sensitivity characteristics to light intensity,characterized in that the image pickup device produces the color andsensitivity mosaic image wherein a plurality of pixels having the samecolor components and the same sensitivity characteristics are arrangedin lattice arrangements and a plurality of pixels of at least one kindfrom among the plurality of pixels having the same color component andhaving the same sensitivity characteristic are arranged so as not toneighbor with pixels of a different kind having the same color componentbut having a different sensitivity characteristic.
 11. (As amended) Animage pickup device as set forth in claim 10, characterized in that inthe color and sensitivity mosaic image, a plurality of pixels having thesame color components irrespective of the sensitivity characteristicsare arranged in lattice arrangements.
 12. (As amended) An image pickupdevice as set forth in claim 10, characterized in that in the color andsensitivity mosaic image, a plurality of pixels having the same colorcomponents irrespective of the sensitivity characteristics are arrangedin square lattice arrangements.
 13. (Added) An image pickup device asset forth in claim 11, characterized in that the plurality of colorcomponents are the three primary color components.
 14. (Added) An imagepickup device as set forth in claim 13, characterized in that the colorand sensitivity mosaic image has a Bayer arrangement where attention ispaid only to the color components irrespective of the sensitivitycharacteristics of the pixels.
 15. (Added) An image pickup device as setforth in claim 10, characterized in that in the color and sensitivitymosaic image, a plurality of pixels having the same sensitivitycharacteristics irrespective of the color components are arranged inlattice arrangements, and that all of the color components included inthe color and sensitivity mosaic image exist in totaling five pixelsincluding an arbitrary pixel and four pixels neighboring upwardly,downwardly, leftwardly and rightwardly of the arbitrary pixel. 16.(Added) An image pickup device as set forth in claim 15, characterizedin that in the color and sensitivity mosaic image, a plurality of pixelshaving the same color components irrespective of the color componentsare arranged in lattice arrangements.
 17. (Added) An image pickup deviceas set forth in claim 15, characterized in that the plurality of colorcomponents are the three primary color components.
 18. (Added) An imagepickup device as set forth in claim 17, characterized in that the colorand sensitivity mosaic image has a Bayer arrangement for each of thesensitivity characteristics of the pixels irrespective of the colorcomponents of the pixels.